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Report No. 2183 Bolt Beranek and Newman Inc.
NIC No. 10916
USER'S GUIDE TO THE TERMINAL IMP
March 1976 Revision
Sponsored by:
Defense Communications Agency
Contract No. DCA200-C-616
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
UPDATE HISTORY
Originally written Dec. 1971 by W.R. Crowther
Updated July 1972 by D.C. Walden
Completely revised Sept. 1972 by D.C. Walden
Updated Oct. 1972 by D.C. Walden
Updated Jan. 1973 by D.C. Walden
Completely revised June 1973 by D.C. Walden
Updated Nov. 1973 by J. Malman
Updated June 1974 by J. Malman
Updated Dec. 1974 by J. Malman
Completely revised August 1975 by J. Malman
Updated March 1976 by J. Malman
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
TABLE OF CONTENTS
1. INTRODUCTION
2. THE NETWORK VIRTUAL TERMINAL
3. THE TIP COMMAND FORMAT
4. TYPICAL USE OF THE TIP
A. Hardware Stage
B. Establishing Parameters
C. Connection to Remote Sites
D. Use of Remote Sites
E. Connection Loss and Restoration
F. TIP News and User Feedback
5. UNUSUAL USES OF THE TIP
A. Device Parameters
B. Talking to Another TIP
C. Binary Mode
D. Setting Another Terminal's Parameters
E. The DIVERT OUTPUT Command
F. Editing
G. Wild
H. Low Level Protocol Commands
I. Commands from the Network
J. The RESET Device Command
K. TIP Configuration and Device Pre-initialization
6. MAPPING THE VARIOUS DEVICES INTO THE NETWORK
VIRTUAL TERMINAL
A. TTY and TTY-like Devices
B. 2741 and 2741-like Devices
C. ASCII/2741 Conversion Table
7. TIP MESSAGES TO THE TERMINAL USER
8. THE TIP MAGNETIC TAPE OPTION
9. CONNECTION OF TERMINALS TO THE TIP
APPENDICES
A. Host Addresses
B. Command Summary
C. Bibliography
D. Terminals Used with the TIP
E. New Telnet Protocol Implementation
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
1. INTRODUCTION
This report describes the use of a terminal connected to a
Terminal IMP (TIP) in the ARPA Network. The report assumes that the
user knows how to operate a server Host system somewhere on the
network once he becomes connected to that system, and the report
defines the procedures and options the user has available to establish
that connection.
The ARPA Network, IMPs and TIPs, hardware maintenance, TIP
operation, and formats and protocols are not described here. The
bibliography (Appendix C) lists the relevant documents.
At the time of this writing we at Bolt Beranek and Newman
Inc. (BBN) have operated the TIP extensively with the following
terminal types:
KSR-33 Teletype
KSR-37 Teletype
IBM-2741 (Correspondence)*
IBM-2741 (P.T.T.C.)*
DATA 100 (at 110, 150, 300, 600, and 1200 bps)
EXECUPORT (at 110, 150, and 300 bps)
INFOTON VISTAR I (at 110, 150, 300, 600, 1200,
1800, 2400, and 9600 bps)
IMLAC PDS-1 (at 1800, 9600 bps, and synchronous)
ODEC 132 LINE PRINTER
TELETYPE INKTRONICS (Line printer)
TI 733
DATA PRODUCTS LINE PRINTER MODEL 2410 or 2411
Where possible, all these devices have been operated with direct
connections to the TIP and also over a 103A dial-up modem.
We have also briefly operated the TIP or heard of the TIP being
operated with a variety of other types of terminals. These are listed
in Appendix D. For your own safety, before you purchase any terminal
listed in Appendix D or any other terminal for use with the TIP, you
should check with BBN and try it with a TIP.
One TIP is configured with a magnetic tape drive which is used as
discussed in Section 8.
It should be noted that the TIP is designed to support
interactive, asynchronous terminals. It cannot normally support
synchronous devices, or devices whose input (to the TIP)
characteristics are significantly different from a human typist. Thus
the connection of computers, paper tape readers, polled circuits,
buffered terminals, and so on to TIP ports is likely to be difficult
or impossible.
---------------
*For a 2741 to operate with the TIP, the 2741 must have the transmit
interrupt option and receive interrupt option.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
2. THE NETWORK VIRTUAL TERMINAL
A key concept in the use of the network is the notion of the
virtual terminal. Instead of asking each Host system to cope with
every terminal type at every other Host in the network, we ask the
Host to cope with a single (imaginary) terminal called the Network
Virtual Terminal. Your TIP will translate the data you type to make
it look like virtual terminal code, and translate the remote system's
response back into your terminal's code. While we will often pretend
that this translation does not exist, it is, in fact, always present
and of crucial importance to the user.
It is probable that the manual describing the use of the remote
system is written in terms of a user at the virtual terminal, most
likely as a system description based on local terminals plus an add-on
piece telling how to use the virtual terminal as a local terminal.
Virtual terminal code may include symbols which do not exist on your
own keyboard. Combinations of your available characters are used in
such cases. You may even find that the translation makes your
terminal different from a local terminal of the same make. We have
tried to minimize this problem.
The Network Virtual Terminal has 128 keys, often in upper
case/lower case pairs. These keys correspond to the full ASCII set.
In addition, there are a few control keys, like the "BREAK" key. The
terminal is capable of full and half duplex operation, under control
of a user-oriented switch. The meaning of the control keys and the
way to enter the full 128 keys from each of the terminal types which
the TIP supports is described in Section 6 of this report.
The user talks to the TIP after the code conversion has been
made; that is, the TIP expects virtual terminal characters. The
descriptions below are in terms of virtual terminal codes.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
3. THE TIP COMMAND FORMAT
The user at a terminal will at various times be talking directly
to his TIP instead of to the remote Host. A typical message of this
sort might look like:
@ OPEN 15
Such a command always starts with symbol @ and ends with either a
linefeed* or a rubout, depending on whether the user is satisfied with
the command or wishes to abort it. The only exception to this rule is
the specific command
@@
which inserts an @ in the data stream to the Host. Commands may occur
anywhere, and need not start on a new line. Upper and lower case may
be freely intermixed in the command.
Between the @ and the linefeed there will typically be one or
more words to identify the command, perhaps followed by a single
parameter. The TIP is not very sophisticated, and thinks the only
important thing about a word is its first letter. This permits the
user to abbreviate a bit; the more usual rendering of the first
example might be:
@O 15
Once the user has started typing the parameter of a command the
old value of the command will have been destroyed, and cannot be
recovered by aborting the command.
Almost without exception the effect of a TIP command is to set a
parameter or mode for the terminal. Even apparently direct commands
like
@ OPEN 15
(which initiates an elaborate exchange of messages resulting in a
connection to the remote Host system) actually set a mode flag to
request the appropriate action when the TIP is free to undertake it.
To understand the TIP behavior is really to understand the complete
set of parameters and the commands to change them. Normally, any
parameter can be changed at any time by the user at his terminal.
Exceptions occur when the user tries to change connection parameters
--------------
*On 2741 terminals the return key transmits carriage-return/ linefeed
to the TIP and ASCII terminals are normally operated in a mode where
typing a carriage-return is interpreted as carriage-return/linefeed;
both can be used to terminate TIP commands in addition to a linefeed
alone.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
on an open connection. An @OPEN 13 executed while talking to Host 15
would generate the error message "Can't" (the connection to Host 15
must be closed before a connection can be opened to Host 13).
Commands often consist of several command words; for example,
@ DEVICE CODE ASCII
Such commands may be abbreviated; for example
@ D C A
The spaces are required: @ DCA is not a legal command. Upper and
lower case letters may be freely intermixed.
An unusual variation in command format is to place a number
between the @ and the first word of the command. In this case, the
command is not meant for the terminal typing but for the terminal
attached to the port of that number on the same TIP as the user. This
feature is described in some detail in the section on unusual uses of
the TIP, section 5.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
4. TYPICAL USE OF THE TIP
In the normal course of things, a user will go through four more
or less distinct stages in typing into the net. First, he will be
concerned with hardware-power, dialing in, etc. Then he will
establish a dialogue with the TIP to get a comfortable set of
parameters for this usage. Next, he will instruct the TIP to open a
connection to a remote Host; and finally, he will mostly ignore the
TIP as he talks to the remote Host. The following sections will
describe these stages in more detail.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
A. Hardware Stage
The hardware stage is primarily described in Section 9. This
section describes only the final step of this stage, when the TIP
detects a terminal on one of its previously idle lines. At that point
the TIP normally goes into a "hunt" mode. In this mode it expects the
very first character it sees to describe the terminal, according to
the following scheme
ASCII Terminals at 110, 150, or 300 baud type E. (Note
that this must be upper case.)
2741 Correspondence Terminals type j, 4, o, or l depending
on the element used with the terminal -- see Table 4-A.
2741 PTTC Terminals type:
6 for model* 938, 939, 961, 962, or 997
o for model 942 or 943
w for model 947 or 948
f for model 963, 996, or 998
ASCII Terminals transmitting at 110 but receiving at
1200 baud type D. (Again, upper case)
The TIP will deduce terminal rate, character size, and code
conversion based on the character typed. When the TIP makes its
decision it types out TIP's name in the terminal's own language
followed by the version number of the TIP software system and the
octal port number. Then it is ready to go. If no TIP name appears,
or if garbage appears, hang up your data set and redial. For direct
connections Power Off is usually equivalent to hanging up.
Some terminals need special delays at the end of their lines in
order not to lose characters when running at high speed. The TIP
currently knows how to do this timing for the ODEC line printer and
several other devices. The two commands
@ DEVICE CODE EXTRA-PADDING
@ DEVICE CODE OTHER-PADDING
will instruct the TIP to insert these delays. One device we know of,
a Model 37 Teletype, requires a special parity computation to be able
to print correctly. The command
@ DEVICE CODE 37
--------------
*The model name and number is stamped on the top of the element. If
you can't find it, trial and error works. Try "f" first.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
instructs the TIP to insert the proper parity; when not in this mode
the TIP sets the parity bit to zero for all output characters. Echoed
characters are echoed without parity calculation. These commands are
discussed more fully in section 5.
On all terminals which hunt to 300 baud, Device Code
Extra-padding (@ D C E) automatically will be in effect. On all
terminals which hunt to 150 baud, Device Code 37 (@ D C 3)
automatically will be in effect. These effects can be canceled with
the command @DEVICE CODE ASCII (@ D C A).
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
TABLE 4-A
Hunt Character to be used for IBM 2741 Correspondence
Type Elements
NUMBER NAME HUNT CHARACTER
001 Scribe 4
005 Letter Gothic 4
006 Manifold 72 j
007 Elite 72 * 4
008 Pica 72 * 4
010 Manifold 72 j
012 Prestige Elite * 4
014 Light Italic j
015 Courier 72 * 4
019 Manifold 72 j
020 Dual Gothic 4
021 Dual Gothic o
025 Scribe o
026 Elite 72 * o
027 Pica 72 * o
028 Manifold 72 o
029 Courier 72 * o
030 Adjutant 4
031 Adjutant o
032 Light Italic o
033 Prestige Elite * o
034 Script o
035 Delegate o
036 Advocate o
039 Letter Gothic o
043 ASCII l
050 Advocate 4
053 Artisan 12-72 4
055 Artisan 12-72 o
059 Orator j
060 Orator o
067 Courier 12 4
068 Courier 12 o
070 Delegate 4
085 Courier 72 4
086 Courier 12 Italic o
090 Script j
123 Prestige Pica o
129 Adjutant o
130 Advocate o
131 Artisan 12-72 o
132 Courier o
133 Courier 12 Italic o
* These type elements can be customized for you. Contact your
local IBM office for information.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
134 Courier 72 o
135 Delegate o
136 Dual Gothic o
137 Elite 72 o
138 Letter Gothic o
139 Light Italic o
140 Manifold 72 o
141 Orator o
142 Pica 72 o
143 Prestige Elite 72 o
144 Scribe o
145 Script o
154 ASCII l
158 Bookface Academic 72 o
161 Large Elite 72 o
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
B. Establishing Parameters
In stage two, the user is concerned with initializing parameters.
The naive user should skip stage two and accept the TIP's default
parameters until an obvious problem arises. The following questions
are answered in stage two.
1. When shall the TIP send off messages to the remote Host? Here
there are several options. (The TIP is inialized to send on every
character, which is simple but inefficient.)
@ TRANSMIT NOW
@ TRANSMIT ON MESSAGE-END
@ TRANSMIT ON LINEFEED
@ TRANSMIT EVERY
TRANSMIT NOW causes the message currently being accumulated to be
sent as soon as possible. TRANSMIT ON MESSAGE-END causes a message to
be sent as soon as possible after an ASCII DC3 (control-S) is
encountered. TRANSMIT ON LINEFEED causes a message to be sent as soon
as possible after a linefeed is encountered. Additionally, both
TRANSMIT ON MESSAGE-END and TRANSMIT ON LINEFEED cause characters to
be accumulated in the message buffer until it is almost full.
TRANSMIT EVERY causes a message to be sent as near as possible to
every th character. The command TRANSMIT EVERY 0 will reset the TIP
to its initial state, transmitting every character. If the parameter
to TRANSMIT EVERY # is a large number (e.g., 250) the TIP will save up
as many characters as it can before sending a message, but does not
offer any guarantee that the total number specified can be buffered.
2. Who shall echo and when? Echoing is a complex problem,
without any neat solution. We have chosen to give the user the means
to tell the TIP how he or she wants it done, since it is hard to guess
correctly in advance. Basically, echoing can occur at the terminal
hardware, in the TIP, or in the remote Host. The corresponding TIP
commands are:
@ ECHO HALFDUPLEX (Echo at the terminal)
@ ECHO LOCAL
or @ ECHO ALL (Echo at the TIP)
@ ECHO REMOTE
or @ ECHO NONE (Echo at the remote Host)
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
Each of these commands sets the internal state of the TIP to the
correct mode, and in addition sends the appropriate TELNET command to
the Host if the connection is open when the command is given. The
commands ECHO ALL and ECHO NONE are now exactly equivalent to ECHO
LOCAL and ECHO REMOTE; they have been left temporarily while users
become accustomed to the new usage.
In the ECHO REMOTE mode, although characters for the remote Host
are not echoed, the TIP will echo commands. Network protocol
specifies that echoing shall start out in the @ ECHO LOCAL or @ ECHO
HALF modes. The TIP will try to guess from the terminal type which of
the two is appropriate. The goal of the echoing strategy is to avoid
the unreadable alternatives of the blank page and the doubling of
every character. The naive user is advised to accept the TIP's
default parameters until trouble of this sort arises. A 2741 cannot
change echo mode and is always halfduplex.
Because both the TIP and the remote Host need to agree on who is
to echo the characters, the TELNET protocol provides a mechanism
whereby the remote terminal user may instruct the serving Host to set
a particular mode and viceversa, the remote Host may instruct the TIP.
As noted above, this happens automatically when the command is given
by the user while the connection is open. But the Host too may issue
such commands to the TIP, and the TIP is not able to refuse the
request (even for 2741 terminals). If the connection becomes
established in an undesirable mode, the user may change this by one of
the echo commands above.
The NEW TELNET protocol handles this mechanism somewhat
differently, as described in Appendix E.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
C. Connection to Remote Sites
In stage three, the user is concerned with establishing a
connection to a remote site.
@ OPEN 15
This amounts to "set the Host number parameter" and "add the user to
the queue of users waiting for the TIP's connection mechanism".
Appendix A lists the Host numbers of all the sites currently in the
network.
Connecting to a Host requires establishing a bi-directional link,
so that the terminal can send characters to the Host and vice versa.
The request to connect to a Host is thus really a request to establish
both transmit and receive sections.
When the user reaches the head of the queue waiting for the TIP's
"connection" mechanism, the TIP will type "Trying...".
Following the message "Trying", the user will receive some of the
following messages:
Open success*
Net Trouble remote site cannot be reached
Refused remote site up but refusing
Host Scheduled Down Until Sat. at 1850 GMT
Host will be back up at time and date
indicated
Host Unscheduled Down Until Sat. at 1850 GMT
Host will back up at time and date
indicated
Host not responding
Remote site not up, unknown when up
service will resume
ICP Interfered With
The Host has not performed the ICP
correctly and the TIP has refused
to open a connection.
The connection mechanism will run continuously until a state
described above occurs. This can be annoying when the remote site is
obviously not going to respond. The command
@ CLOSE
---------------
*"Open" indicates both halves of the TELNET connection have been
opened simultaneously. Sometimes "Open R" followed by "Open T" (or
vice versa) will be printed; this too indicates both halves of the
connection have been opened, but not simultaneously. If only "Open R"
or "Open T" is printed, then the server Host has failed to open one
half of the TELNET connection.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
will abort the current connection attempt. The user is then free to
reattempt to open the connection or to attempt to open a connection to
some other Host.
The TIP's connection mechanism has caused users some problems.
Perhaps a discussion of what the connection mechanism is doing and how
it works will alleviate some of the grief.
First of all, users attempting to connect to different Hosts will
never interfere with each other, although users simultaneously
attempting to connect to the same Host will be serviced serially.
For the user, opening proceeds in three phases. In the first,
the user is queued up waiting to "get" the TIP's connection mechanism.
In the second, the user has gotten the TIP's connection mechanism and
is beginning the connection sequence. In the third, the user has
completed the connection sequence and is waiting for the Host to open
up the actual data connections. Many of the problems stem from the
fact that only one user may be proceeding through phase 2 at a given
time to a given Host. Hence the the TIP types out "Trying" when you
get off the queue and the connection mechanism begins trying to open
your connections. Thus the "Trying" message signifies the transition
from phase 1 to phase 2.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
D. Use of Remote Sites
In stage four, the user is normally talking to the Host without
concern for the TIP. All the TIP commands are still available.
One command that will eventually be of interest here is
@ CLOSE
This command starts the shut-down procedure. The TIP will echo
"Closed"* when the process is finished. The TIP does not know how to
log you out of the remote Host. You must do this yourself before
closing the connection.
The virtual terminal has a key labeled "BREAK". Some real
terminals have a break key, and some Host systems expect to see
breaks. Those terminals with a break key (but not the 2741 ATTN key)
may simply use it. Others must type the command
@ SEND BREAK
The interpretation of the break is entirely up to the receiving Host
-- many Hosts ignore it.
The virtual terminal also has a key labeled "SYNC". No real
terminals have such a key, and the function is unique to network use.
The "SYNC" key is a clue to the remote Host that there is an important
message which seems to be buffered in an "inaccessible" place. The
TIP and the Host go to some trouble to get the SYNC indication over a
different channel which bypasses the normal buffering conventions.
The command to send a SYNC is
@ SEND SYNC
Typical usage of these commands might be @ S B followed by @ S S.
As stated earlier, the TIP nominally treats a carriage- return
typed by a user as a carriage-return/linefeed. The user may cause the
TIP to treat carriage-return as only carriage-return by executing the
command
@CLEAR INSERT LINEFEED
-----------------
*"Closed" indicates that the server Host agreed to close both halves
of the TELNET connection simultaneously. If the halves of the
connection are closed one after another, "Closed R" followed by
"Closed T" (or vice versa) will be printed. If only one of "Closed T"
or "Closed R" is printed, wait a minute and the TIP will force the
other half of the connection to be closed.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
To return to the nominal mode of carriage-return/linefeed, the command
@INSERT LINEFEED
should be executed.
If at any given time the user types characters faster than a
server Host will take them from the TIP, the TIP discards characters
it can not buffer and echos them with an ASCII BEL (on a 2741, the
type element is wiggled).
The user may sometimes use a server Host with which it is
desirable not to have @ be a TIP reserved character. The user can
change the character which introduces TIP commands using the command
@INTERCEPT #
By typing @INTERCEPT followed by a decimal number representing an
ASCII character, the user changes the TIP command character for his
device to the ASCII character represented by the number. The
INTERCEPT ESC command resets the TIP command character to at-sign (@).
Thus,
@INTERCEPT 42
*INTERCEPT ESC
changes the TIP command character to asterisk (*) and back to at-sign
(@) assuming the device was in the nominal mode (@) before the first
command was executed.
If the user attempts to change the intercept character but fails
to type a valid decimal number (or a character string beginning with
E) the TIP will type the diagnostic "Num" and will set the intercept
character to at-sign.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
E. Connection Loss and Restoration
Starting with TENEX Hosts* running Software Version 1.32, if
TENEX halts, the TIP will notify users connected to it of this fact by
typing "Connection Suspended". At this point the users are free to do
one of two things. First, they can wait till TENEX restores service,
in which case the TIP will type out "Connection Restored" (or if after
the the service interruption the connection could not be restored, the
TIP will type out "Host broke the connection"). Alternatively, the
user is free to open a connection to any other Host, in which case the
TIP will invisibly close the TENEX connection. It is also important
to point out that if a user just leaves his terminal unattended across
a TENEX service outage without releasing the connection (any network
related command such as @H, @O, @N, @C will do the job) his job,
directory, etc., are left at the mercy of anyone who acquires that
terminal.
-------------------
Other Hosts may also implement the mechanisms which will allow
the suspension and restoration of connections.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
F. TIP News and User Feedback
There is frequently information which the group developing and
debugging the TIP system wishes to convey to TIP users. For instance,
when a bug is detected, we may wish to warn users not to use a certain
feature until the bug is fixed. When a minor improvement is made, we
may wish to notify users. Further, there is frequently news about the
state of the network or the state of a particular Host which should be
conveyed to TIP users. Finally, TIP users may wish to communicate
with the TIP development staff or the Network Control Center staff
about problems or suggested improvements for the TIP or the network.
Consequently, we have constructed a mechanism which we hope will
provide for communication in all the above directions. This mechanism
is the Network Virtual TIP Executive.* To activate this mechanism, the
TIP user may give the TIP command @N. This command causes the TIP to
perform the necessary protocol to make a connection to the Network
Virtual TIP Executive which resides on several of the network TENEX
systems. Once the Network Virtual TIP Executive has been activated,
we think its operation is self-explanatory. Presently available
features within the Network Virtual TIP Executive are a Network News
feature, a Host Status feature, and a "Gripe" feature. The latter
provides users with a mechanism for sending messages to the TIP
development or NCC staffs. We recommend that TIP users get the
network news at the beginning of every TIP session.
The TIP will normally prompt the user to consider reading the
news by typing the message:
Latest net news DATE
Use "@N<cr>" followed by "netnews<cr>"
at some point(s) during the user's session. The point chosen is at
the time of terminal recognition for "hunting" terminals (see Section
4.A), or at each time a connection is closed for "non-hunting"
terminals (see Section 5.A).
When a user issues an @N command, the TIP requests support from
all cooperating servers. Thus, the user should be able to reach a
←←←
news facility, somewhere, almost all of the time. However, in the
event that no cooperating server is available the TIP will time out
the @N command in about thirty seconds. An @C command will abort an
@N immediately.
Of course, TIP users with an immediate need for communication
with the NCC or TIP development staffs should telephone (collect) the
Network Control Center (617-661-0100). Users with general questions
----------------
*A version of the Resource Sharing Executive being developed by the
BBN TENEX Group.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
about network usage (How do I find out if Host X is ever going to be
up again? What's happening with a Host/Host protocol for graphics?)
may also call the NCC.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
5. UNUSUAL USES OF THE TIP
The "usual" use of a TIP is to connect one of the terminals which
the TIP supports to a remote Host. We have tried to make this
operation as easy and natural as possible for the user. "Unusual"
uses of the TIP are such things as connecting a non-standard terminal,
talking terminal-to-terminal, or using unusual protocols. Such uses
are possible, but within the constraints of the TIP's size it has not
always been feasible to make them easy.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
A. Device Parameters
The TIP uses a Hunt algorithm to determine device parameters. On
standard low speed terminals it works well and easily. If something
more complicated is desired, like establishing a rate over 300 bps,
the user must set these parameters himself.
The @DEVICE RATE command does not affect the hunt-bit.
Therefore, the only way to change a port to, or from, being hunting is
to have the TIP site liaison call the NCC and have it done.
The TIP stores device parameters in a 10-bit field as shown
below:
bits
-.-.-.-.-.-.-.-.-.-.-
! 4 ! 2 ! 4 !
-.-.-.-.-.-.-.-.-.-.-
! ! !
! ! ---Input rate
! !
! ---Character size
!
---Output rate
where character size is 5 less than the number of bits per character
and the 16 rates are zero, 75, 110, 134.5, 150, 300, 600, 1200, 1800,
2400, 4800, 9600, 19200, unused, unused, and external clock. The
4800, 9600 and 19.2K rates are available only for output.
The user can change device parameters with the command
@ DEVICE RATE #
where # is the decimal equivalent of the 10-bit field the user wishes
to establish. The command will often be executed from another
terminal (see Section 5-D below).
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
Some examples follow:
@D R bps
178 110 ASCII in and out
308 150
373 300
438 600
503 1200
568 1800
633 2400
754 110 in 9600 out
243 134.5 2741 in and out
The user can set device code conversion with the commands
@ DEVICE CODE ASCII
@ DEVICE CODE EXTRA-PADDING
@ DEVICE CODE OTHER-PADDING
@ DEVICE CODE 37
EXTRA-PADDING is ASCII with a slow carriage-return. This mode has
been found to be useful with EXECUPORT, T.I., AND DATAPOINT 3300.
DEVICE CODE OTHER-PADDING is ASCII for a line-printer which requires
special timing for a slow linefeed as well as a slow carriage-return
and also requires a minimum number of characters per line of output.
Two line-printers are currently handled via the DEVICE CODE
OTHER-PADDING option. These are the ODEC printer and the MEMOREX
printer. A given TIP can be configured so that DEVICE CODE
OTHER-PADDING refers to either the ODEC or the MEMOREX printer but not
both.
Often the device code commands will be executed by one terminal
for another terminal, as described in Section 5-D below. Sometimes
they are executed as the last step before changing a terminal's rate.
The code sets ASCII, EXTRA-PADDING, and OTHER-PADDING are similar
enough so that a terminal shifting from one to another will still be
able to talk to the TIP. All are basically ASCII with different
timing for the end of line. DEVICE CODE ASCII clears the effect of
the other three DEVICE CODE commands. The command
@DEVICE CODE 37
can be used to set up the TIP to correctly handle a Model 37 Teletype,
namely to compute even-parity for output characters (echoed characters
have the parity they had when sent from the terminal to the TIP).
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
B. Talking to Another TIP
One can talk to a device on another TIP (or your own TIP) using
the TIP as a fancy telephone connection. This is not particularly
easy, especially since the only label a TIP knows for a device is its
hardware port number, which neither user may happen to know.
Supposing the port numbers are known, one must establish a pair of
connections between the two ports. The protocol for making
connections specifies that each end of each connection will be labeled
by a 32-bit socket number. The TIP puts the port number in the high
order 16 bits of the socket number, and 2 (or 3) in the low order bits
for the receiving (or sending) socket. The user must tell the TIP the
Host number (in decimal) and socket number (in octal) for the foreign
end of both the transmit and receive connections, for example, the
commands
@ SEND TO HOST 158
@ RECEIVE FROM HOST 158
@ SEND TO SOCKET 1600002
@ RECEIVE FROM SOCKET 1600003
Simultaneously the far end must establish the corresponding parameters
for his half of the connection. Then one side or the other must
initiate the connections using the two commands
@ PROTOCOL TO TRANSMIT
@ PROTOCOL TO RECEIVE
This will open the full duplex connection. In the example above the
connection is to Port 7 at Host 158. Alternately, a shorter sequence
of commands may be used, namely
@ HOST 158
@ SEND TO SOCKET 1600002
@ RECEIVE FROM SOCKET 1600003
@ PROTOCOL BOTH
If the terminals are full duplex, it will probably be necessary
for each terminal to use ECHO ALL mode.
A problem in making TIP-to-TIP connections is ascertaining the
port numbers of the TIP ports between which communication is desired.
The greeting message typed by the TIP on a hunting port includes the
octal port number. The @RESET command on non-hunting ports also
provides this information (although it also logs out a logged-in
user). In addition, the The Network Virtual TIP Executive (@N) offers
aid in this area through its TRMINF command. The socket number
printed by the TRMINF command is the octal port number of the TIP
terminal executing the TRMINF command via the @N command.
In the future, we will make available via the Network Virtual TIP
Executive a capability to link and send messages to users on other
TIPs and TIP ports by name. The capability already exists in the
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
Network Virtual TIP Executive for linking to users of some server
Hosts.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
C. Binary Mode
Seven-bit binary is possible using the regular TELNET Protocol.
It is necessary to turn on and off command interpretation to allow the
TIP input routines to pass along all 128 possible input characters.
There are two commands to do this,
@ INTERCEPT ESC
@ INTERCEPT NONE
The first command puts the TIP in its normal mode, the second in 7-bit
binary mode.
Eight-bit binary mode is possible using the commands
@ BINARY INPUT START
@ BINARY INPUT END
@ BINARY OUTPUT START
@ BINARY OUTPUT END
When a TIP is in binary output mode, all eight bits of characters
coming from the network are sent to the terminal. This may result in
strange things being printed on a printer. It would probably make
more sense to send 8-bit binary output to devices such as paper tape
punches. When a TIP is in binary input mode, all eight bits of
characters entered at the terminal are sent to the network.
Since commands from a terminal in binary input mode or INTERCEPT
NONE mode can no longer be recognized, removing a terminal from these
modes must be done with a command from another terminal as described
immediately below. As the TIP's default mode is INSERT LINEFEED, the
user will probably desire to CLEAR INSERT LINEFEED (@C I L) before
using 8-bit binary mode; perhaps also for 7-bit binary mode.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
D. Setting Another Terminal's Parameters
Any command may be preceded by a number, in which case it is
meant for a device other than your own. The device port number must
be in octal. For example,
@ 16 DEVICE RATE 633
would set the characteristics for device 16 to ASCII code, 2400 baud
input and output. In this case we speak of "capturing" device 16.
Such a mechanism needs some form of protection: the TIP remembers
the number of the capturing device and does not allow a second device
also to capture until the first device explicitly gives up control
with the command
@ 16 GIVE BACK
If a device chooses to capture himself by preceding any command
by his own device number he is then invulnerable to tampering from
another device.
This format is usually used in conjunction with the DEVICE RATE
command to initialize some non-standard device, like a printer or a
high-speed CRT terminal.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
E. The DIVERT OUTPUT Command
It is possible (with some care) to divert the output intended for
one terminal to another terminal. Presumably the second terminal has
a desired feature, like hard copy or high speed. The command
@ 16 DIVERT OUTPUT
will cause all remotely generated output to be diverted from the
terminal on which the command was typed to Terminal 16. This state
will continue until any other command is executed at the diverting
terminal. (Executing another command does not do a Give Back.)
Local-echoing will not be diverted, and input may proceed at the
diverting terminal.
This mechanism is not natural to the structure of the program.
In particular, the buffer allocation structure becomes confused if the
diversion aborts while output is in progress. Chained diversion will
also confuse the TIP. Please don't try these things: all that will
happen is that one or both terminals involved will stop responding.
In fact, in general, we discourage use of the DIVERT OUTPUT command
and suggest printing to TIP devices other than the user's own terminal
by programs such as the TIPCOPY program which runs on many network
TENEXs.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
F. Editing
At the moment the only editing command available is
@ FLUSH
which deletes all the characters in the TIP's input buffer. In
current practice this command is used to clear out any odd characters
stuck in a TIP prior to giving an OPEN command. (The TIP accumulates
characters typed in during periods of non-connection and sends them as
the first data over a new connection.)
To abort a command, type a rubout or merely make something about
the command illegal; for example,
@O X
The "X" aborts the OPEN command.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
G. Wild
Setting a device wild allows the device to receive any connection
from a designated Host or to receive any connection from any Host.
TIP ports cannot be set permanently wild from other TIP ports, they
must be set wild by the NCC. The command to set a port wild is
@SET DEVICE WILD
This instructs the TIP to accept an attempt to connect from any Host
using any sockets. This command can be cancelled by the command
@CLEAR DEVICE WILD
If a user desires to accept an attempt to connect from a particular
Host using any sockets the set of commands
@HOST #
@SEND TO WILD
@RECEIVE FROM WILD
should be used. This instructs the TIP to accept any attempt to
connect from the Host whose decimal address is specified in the Host
command.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
H. Low Level Protocol Commands
Several low level TIP commands exist which allow the user to
manually do Host/Host protocol. These commands are
@ INITIAL CONNECTION PROTOCOL
@ PROTOCOL BOTH
@ CLOSE
@ PROTOCOL TO TRANSMIT
@ PROTOCOL TO RECEIVE
@ RECEIVE FROM HOST #
@ SEND TO HOST #
@ HOST #
@ SEND TO SOCKET #
@ RECEIVE FROM SOCKET #
Examples of the use of some of these commands are given below.
@H 69 /"logging in" to a socket
@R F S 13 /other than socket 1
@I C P /on a server Host
@C /attempt to close both halves of
/an open connection
Closed R /closed R side of connection
Closed T /closed T side of connection
The rest of the low level protocol commands listed above were used in
the example of section 5-B.
There is one other low level protocol command, a command to reset
the NCP in the Host specified in a @ SEND TO HOST command. Since this
command resets all connections between the TIP and the specified Host,
it should only be used as a last resort. A responsible person at the
TIP site should contact the NCC if the need arises.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
I. Commands from the Network
When a TIP terminal receives the character 207 (octal) in the
input stream from the network, the characters following the 207 up to
the next linefeed are treated as a command typed on the terminal
keyboard. (The 207 takes the place of the @; the @ should not be sent
through the network.) In this way Hosts can remotely control the TIP
terminals. For example, a Host might send a command to the TIP which
causes maximum size messages to be sent from the TIP terminal to the
Host. The TIPs themselves can send commands to other TIP terminals by
using the command
@ SEND COMMAND
which inserts the 207 character in the output stream to the network.
This feature is evolving, so we do not recommend its use at the
present time.
It must be noted that this 'feature' is ONLY available under the
OLD TELNET protocol. In theory, NEW TELNET will provide the same
capabilities within the framework of the protocol itself rather than
as a special mechanism for TIPs. As of this writing, however, not all
the comparable options have been implemented.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
J. The RESET Device Command
The reset device command (@RESET) will restore a port to its
initial state. Implicit in this command is the concept of a
"permanent device." Currently, "permanent" is the same as
"non-hunting" (see section 5-A), but this will not always be so.
Permanent devices are those requiring a particular set of parameters
that is not expected to change or perhaps for which the TIP cannot
hunt. Examples are the IMLAC (no high speed hunt) and a line printer
(no input possible). Everything is reset as follows:
a. All network connections and attempts to open connections
are cleared;
b. If this device is captured by any other device, that
state is cleared and if this device is capturing any
other devices, that state is cleared;
c. Input buffers are initialized;
d. "Connection" parameters are reset to a default state*
(i.e., echoing all, terminate every character, no insert
linefeed, no device wild, intercept all);
e. The code, rate, and size are set to the hunting state.
f. The port's data set is hung-up.
g. Sets the terminal to make connections under OLD TELNET
protocol.
For permanent devices the RESET command does only a, b, c, f, and g
above and prints "TIP NAME" followed by the TIP version number and the
octal port number.
-----------------
*The default state for "binary" mode (Section 5.C) is rather
complicated and is being somewhat revised. For current infor-
mation, contact the NCC.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
K. TIP Configuration and Device Pre-initialization
The set of terminals and uses of these terminals typically varies
from TIP site to TIP site. Therefore, the TIP software system has
been constructed in a way which is somewhat modular to permit varying
configurations of the TIP software at different sites. For instance,
with line printers, it is possible for a given TIP system to contain
code to handle an ODEC line printer or a MEMOREX line printer or
neither (not both). As another example, it is possible to distribute
the available space for device buffers among all sixty-three TIP ports
or to allocate the available space to only a few ports (thus
effectively disabling the remaining ports). Finally, it is possible
to configure the TIP so certain ports are automatically set up to have
pre-determined parameters at TIP initialization time, thus relieving
TIP site personnel or users of the burden of manually setting up these
device parameters.
The complete list of presently available options is given below:
1. TIP configured with ODEC code or MEMOREX code or neither.
2. TIP configured with EXTRA-PADDING code or without it.
3. TIP port pre-initialization
a. Input buffer size
b. Output buffer size
c. Input rate
d. Output rate
e. No hunt or hunt (see section A)
f. Extra-padding (D C E) or not
g. Other-padding (D C O) or not
h. Wild (S D W) or not
i. No insert linefeed (C I L) or not
j. Half duplex (E H) or not
k. No intercept character (I N) or any intercept
character
l. Echo none (E N) or not
m. Compute 37 parity (D C 3) or not
Of the above, f, g, and m are mutually exclusive, j and l are mutually
exclusive, and f through m depend on e being set to no hunt.
Some configuration must be specified for each TIP. If nothing is
specified by the TIP site personnel, the TIP will be configured in an
arbitrary (but hopefully reasonable) manner. Requests for specific
TIP configurations should be made by the designated representative of
the TIP site to the Network Control Center.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
6. MAPPING THE VARIOUS DEVICES INTO THE NETWORK VIRTUAL TERMINAL
A. TTY and TTY-like Devices (ASCII)
At the moment this conversion follows the simple rule that if the
terminal can generate and/or print the code it will be sent and/or
received. Otherwise there is no way to use the code. For example,
there is no way to enter lower case characters from a Model 33
Teletype.
B. 2741 and 2741-like Devices (transmit interrupt and receive
interrupt options required)
The rule for these devices is if the terminal has the ASCII
graphic it will translate directly to that graphic. Otherwise a
number of equivalences are defined, most of which consist of the
character double-quote followed by some other character. For each of
the eight variations of 2741 that we have considered there is at least
one way to type in the desired ASCII graphic. To actually type in the
character double quote, two double quotes must be struck in
succession. On output, ASCII characters which print on a Model 37
Teletype but have no representation on a 2741 are printed as the
equivalents used to type in the character, with some exceptions.
ASCII characters which do not print on a Model 37 Teletype do not
print on a 2741. A double quote is not printed as two double quotes;
thus, on output the user must sometimes determine what was printed
from the context as there is no unambiguous representation of all the
ASCII characters.
The ATTN key is used to interrupt output. It signals the TIP to
hold off output for the duration of one TIP command; it is not seen by
the remote Host. If used during input it is taken as a request to
send all the accumulated characters to the remote Host (like @TRANSMIT
NOW).
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
C. ASCII/2741 Conversion Table
If this table is printed on-line, it is meant to be printed on a
printer possessing the full ASCII character set. Except where noted,
on input, any of the alternate 2741 representations of the ASCII
character which it is possible to type on the given 2741 may be used.
On output, the single character representation is chosen when
possible. In the "Symbol" column of the table, ↑ is used to indicate
control; e.g., ↑R means control-R. Not all ASCII terminals have a
left arrow -- some have an underbar instead. Likewise, some ASCII
terminals have a caret where others have an uparrow.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
ASCII ASCII 2741
Octal Decimal Name Symbol Representation
0 0 NUL ↑@ "P (no output)
1 1 SOH ↑A "a (no output)
2 2 STX ↑B "b (no output)
3 3 EXT ↑C "c (no output)
4 4 EOT ↑D "d (no output)
5 5 ENQ ↑E "e (no output)
6 6 ACK ↑F "f (no output)
7 7 BEL ↑G "g
10 8 BS ↑H "h or BS (output only)
11 9 HT ↑I "i or HT (output only)
12 10 LF ↑J "j or LF (output only)
13 11 VT ↑K "k (no output)
14 12 FF ↑L "l (no output)
15 13 CR ↑M "m or NL (output only)
16 14 SO ↑N "n (no output)
17 15 SI ↑O "o (no output)
20 16 DLE ↑P "p (no output)
21 17 DC1 ↑Q "q (no output)
22 18 DC2 ↑R "r (no output)
23 19 DC3 ↑S "s (no output)
24 20 DC4 ↑T "t (no output)
25 21 NAK ↑U "u (no output)
26 22 SYN ↑V "v (no output)
27 23 ETB ↑W "w (no output)
30 24 CAN ↑X "x (no output)
31 25 EM ↑Y "y (no output)
32 26 SUB ↑Z "z (no output)
33 27 ESC ↑[ "K or
cent-sign (no output)*
34 28 FS ↑\ "L (no output)
35 29 GS ↑] "M (no output)
36 30 RS ↑↑ "N (no output)
37 31 US ↑← "O (no output)
-----------
*A cent-sign will print if the 2741 has one, otherwise
there will be no output.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
40 32 SP space space
41 33 ! ! or plus-minus-sign
42 34 " "" (input) and " (output)
43 35 # # or "=
44 36 $ $ or "&
45 37 % % or "?
46 38 & & or "$
47 39 ' ' or ",
50 40 ( ( or "<
51 41 ) ) or ">
52 42 * *
53 43 + + or sideways-group-mark
54 44 , ,
55 45 - -
56 46 . .
57 47 / /
60 48 0 0
61 49 1 1 or degree-sign or box
62 50 2 2
63 51 3 3
64 52 4 4
65 53 5 5
66 54 6 6
67 55 7 7
70 56 8 8
71 57 9 9`
72 58 : :
73 59 ; ;
74 60 < < or "(
75 61 = = or delta-sign
76 62 > > or ")
77 63 ? ?
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
100 64 @ @ or "+
101 65 A A
102 66 B B
103 67 C C
104 68 D D
105 69 E E
106 70 F F
107 71 G g
110 72 H H
111 73 I I
112 74 J J
113 75 K K
114 76 L L
115 77 M M
116 78 N N
117 79 O O
120 80 P P
121 81 Q Q
122 82 R R
123 83 S S
124 84 T T
125 85 U U
126 86 V V
127 87 W W
130 88 X X
131 89 Y Y
132 90 Z Z
133 91 [ [ or "B
134 92 \ \ or "/
135 93 ] ] or "E
136 94 ↑ caret or uparrow or "! or
"plus-minus-sign
137 95 ← underbar or slash-b
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
140 96 ` "*
141 97 a a
142 98 b b
143 99 c c
144 100 d d
145 101 e e
146 102 f f
147 103 g g
150 104 h h
151 105 i i
152 106 j j
153 107 k k
154 108 l l
155 109 m m
156 110 n n
157 111 o o
160 112 p p
161 113 q q
162 114 r r
163 115 s s
164 116 t t
165 117 u u
166 118 v v
167 119 w w
170 120 x x
171 121 y y
172 122 z z
173 123 { "6
174 124 | vertical-bar or "V
175 125 } "9
176 126 tilde } not-sign or "underbar
177 127 DEL rubout "D (no output)
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
7. TIP MESSAGES TO THE TERMINAL USER
BAD The TIP doesn't recognize the command
Closed Connection closed, usually by server Host
Connection Restored
Destination Host has restored the connection as it
was before the Host halted.
Connection Suspended
Destination Host has halted operation.
Host broke the connection
The Destination Host's service is restored but all
network connection tables have been reset.
Host not responding
Destination Host not up from the network's point
of view. It is not known when service
will resume.
Host Scheduled Down Until ...
Destination Host is scheduled down until the
date and time indicated.
Host Unscheduled Down Until ...
Destination Host is unscheduled down until the
date and time indicated.
ICP Interferred With
The Host has not performed the ICP correctly
and the TIP has refused to open a connection.
Latest Net news...
Use "@N<cr>" followed by "netnews<cr>"
The TIP is conveying to the user the date the
latest news item for TIP users was generated.
Net Trouble Destination IMP cannot be reached due to some
kind of trouble in the network.
NO Parameters may not be set for specified terminal.
Num The TIP expected a number -- command terminated.
Open Connection opened by server Host.
R Refers to the Receive side of a connection.
Refused The remote Host rejected the attempt to establish
connections.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
T Refers to the Transmit side of a connection.
TIP GOING DOWN The TIP is going down in the number of minutes
indicated -- quickly stop what you are doing
and stop using the TIP.
TIP NAME The TIP heard the user dial in and establish rate.
The number following NAME is the TIP software
system version number. It is followed by the
octal port number.
Trying The TIP is now servicing the user's OPEN request.
Wait The TIP is attempting to contact an RSEXEC Server.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
8. TIP MAGNETIC TAPE OPTION
As one method of increasing the usefulness of the Terminal IMP,
we have developed a magnetic tape transfer capability as a TIP option.
The first such option was delivered to the field during the first
quarter of 1972. In order to ease the problems of interfacing such a
specialized terminal type, we chose to specify the attachment of a
standard Honeywell peripheral unit rather than attempting to solve the
problem of tape drive attachment in a more generalized way. The unit
chosen is the Honeywell 316-4021 option which consists of a tape drive
controller and one drive unit (the controller itself is capable of
handling up to seven additional 316-4022 drives). The characteristics
of the tape drive include:
- Read/write speed of 26 inches per second
- Seven-track tapes
- Even or odd parity (program selectable)
- Industry compatible 200, 556, or 800 bpi
In addition to the tape drive and controller, the problem of
programming for the controller and the buffering of tape records
dictated the addition of a separate 4K memory bank to TIPs equipped
with this option.
The most immediate pressure for the addition of a magnetic tape
option to the TIP was the desire to enable a pair of TIP users to copy
tapes over the network from one TIP to another, rather than shipping
physical tapes by mail.
The magnetic tape system communicates with the network through
the TIP, although in many cases it bypasses the usual TIP code,
substituting its own procedures to allow for the special nature and
relatively high data rate of a magnetic tape terminal. In most
respects, however, the tape unit appears as a standard terminal,
arbitrarily designated number 77. On a TIP equipped with magnetic
tape, line 77 cannot be used as an external terminal.
An additional terminal is required to issue commands to the tape
and receive status information and error comments. This may be of any
type and may be connected to any line. Its use as the
tape-controlling terminal can be concurrent with its normal usage.
The specific hardware design of the magnetic tape units used
dictates some constraints. Tape format is 7-track using either odd or
even parity. In memory, tape frames are stored two to a word
occupying the high order twelve bits of each word. Frames can only be
written in pairs; reading a record with an odd number of frames causes
the control unit to append an extra null frame to the record in
memory.
The maximum record length is 2400 characters (frames). This
limit is based on the amount of TIP core available for buffering. If
all maximum length records are used, this results in an 80%
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
utilization of tape space at 800 bpi (the remainder is inter-record
gaps).
The commands relating to magnetic tapes are of a less general
form than other TIP commands. Neither multiple spaces nor word
completion are presently permitted, and numbers are used to
distinguish different commands. The format is @ M #1 #2, where #1 and
#2 are the command number and its argument respectively. The
commands, their numbers and arguments are:
Rewind 1 decimal-count
Forward Space Record 2 decimal-count
Forward Space File 3 decimal-count
Backward Space Record 4 decimal-count
Backward Space File 5 decimal-count
Read Record 6 decimal-count
Read File 7 decimal-count
Write Record 8 decimal-count
Write File 9 decimal-count
Transfer Files 10 decimal-count
Setup TIP-TIP Copy 11 foreign-TIP-number
Abort and Initialize 12 parity (i.e. even or odd)
Write File Mark 13 decimal-count
Set Parity 14 even-or-odd
A file mark is treated by the hardware as a record and must thus be
accounted for when spacing or reading by the RECORD commands. The
SETUP COPY command is used in the establishment of a connection
between TIPs, described below.
There are some important things to note about magnetic tape
commands. All regular TIP commands given for the tape, e.g., those
specifying Host or socket parameters, must be preceded by 77. This,
of course, captures the tape drive for the terminal giving the
commands. All special tape commands (those beginning with M),
implicitly capture device 77 in the same way. Thus once any terminal
issues a command for device 77 or any MAG command, it has captured the
magnetic tape; no one else is permitted to control it until the owning
terminal has issued the @77 GIVE BACK command.
A network connection must exist before information may be
transferred. A typical sequence of TIP commands which might establish
a connection between two magnetic tapes follows: at each TIP, the
operator would issue a Setup Copy command to the Host number of the
other TIP. This command establishes socket numbers for the "standard"
TIP-to-TIP magnetic tape connection. Status information about this
connection such as Open, Closed, etc. will be followed by MTR and MTT
rather than the usual R and T to differentiate magnetic tape activity
from other activity of the controlling terminal. Then the write side
would give a Transfer Files command which would close MTT and MTR if
necessary, and open MTT. When MTT opens, a request is sent to the
other TIP, and MTT is closed. The request prompts the other TIP to
open MTR (his MTT), rewind his tape, read and send the requested
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
number of files, rewind his tape, and close the connection. The
writing TIP also rewinds its tape after writing the last file.
Errors and abnormal status conditions are detected and messages
are typed out on the controlling terminal. Errors which will be of
significance to the operator include:
UNREC ERR Unrecoverable read or write errors
after 20 retries -- a bad spot in
the tape or tape drive hardware
problems. The results of the
20th try are used.
TIMEOUT The tape controller remains busy
or no network activity occurs for
too long. The command is aborted.
OFFLINE The mag tape unit is somehow not
operational (power off, no tape
mounted, vacuum off, wrong unit
number, etc.). The command
is aborted.
EOT The tape has moved past the end-of-tape
marker. The command is aborted.
The error messages may be followed by MTR or MTT to denote which side
of the connection originated the message. At the request of the TIP
sites with magnetic tape option, records read in error presently are
reread many times and then transmitted anyway after printing an error
message. If aborted by an error condition, the Transfer Files command
will attempt to restart the transfer requesting the other TIP to
rewind its tape, skip over as many files as have already been written
and send the remaining files.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
9. CONNECTION OF TERMINALS TO THE TIP
A. General Comments
The TIP allows the connection of most terminals that conform to
the EIA RS232 standard. The TIP is built such that it appears to a
terminal to be a modem and appears to a modem as a terminal. If a
terminal has a 25 pin connector (DB25P, several manufacturers) and
works with a 103 modem or equivalent, it will probably work when
plugged into an LIU card marked "T". Appendix D lists terminals that
have been used.
This section specifies the interface between a terminal and the
TIP. See Section 9-C for connections involving modems. It is hoped
that by examining this section, an engineer will be able to determine
whether he has met the conditions necessary for proper operation of a
terminal connected to the TIP.
To a large extent, the TIP follows EIA Standard RS-232C.
Familiarity with that document is recommended. (The pin allocations
specified by that standard are given inside the front cover.)
In order to connect a terminal to the TIP without modems, one
must look like a modem to the other. Input and output connections are
therefore cross-connected at the LIU pads, as shown in Table 9-1.
Expansions to this specification are planned in the future
(particularly as this relates to control signals). It is therefore
very important that this section be kept up-to-date as revisions are
provided.
Connector - The connector from the terminal should be equivalent
to a Cinch DB-25P. It is recommended that extension cords for
terminals provide for all 25 pins in order to allow for future
changes.
Signal Levels - All signals are represented by bipolar low
voltage levels. All signals are measured with respect to signal
ground. The source of a signal shall deliver a voltage of magnitude
between 3 and 25 volts into a load of not less than 3000 ohms. The
reactive component of the load shall not be inductive, and the
capacitance shall not exceed 2500 pfd. measured at the interface
connector. The signals shall be interpreted in this way:
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
Data Signals
-25<Vd<-3 is marking or logical one
+3<Vd<+25 is spacing or logical zero
Control and Timing Signals
-25<Vc<-3 is considered OFF
+3<Vc<+25 is is considered ON
Signal Use - The TIP software handles the signals as shown in
Table 9-1.
Character Code - The TIP software accepts ASCII 8-bit code.
Parity is ignored on input, and undefined on output. IBM 2741 and
2741-like devices are specially handled. See Section 4-A.
Carriage Return Speed - Carriage return speed is known to be
reasonably compensated for Teletypes 33, 35, and 37; and, separately,
for Execuport-like devices. A line printer (ODEC) with a small
(256-character) buffer is also reasonably compensated. This
compensation is set by the TIP program.
Terminals Which Provide Their Own Clock - Terminals which provide
their own clocks for transferring data can be connected to the TIP
provided they meet the previous specifications. The clocks should be
routed to LIU pads E15 and E17. The data lines should change on the
positive edges of the clocks, and should be sampled on the negative
edges. (This is not to be interpreted as an indication that the TIP
works with synchronus modems or devices. Characters must still be
formatted with stop-start bits since the actual operating mode is
basically character-asychronus.)
B. Direct Terminal Connection
Table 9-1 lists how the TIP uses RS232 signals for terminal
connections.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
TABLE 9-1 TIP SIGNAL ALLOCATION FOR TERMINALS*
EIA LIU DESIGNATION
PIN PAD (FROM THE POINT OF VIEW OF THE TERMINAL)
1 E1 PROTECTIVE GROUND (AA) - Used.
2 E3 TRANSMITTED DATA (BA) - Used for data going from
the terminal to the TIP.
3 E2 RECEIVED DATA (BB) - Used for data going from the
TIP to the terminal.
7 E7 SIGNAL GROUND (AB) - Used.
8 E20 RECEIVED LINE SIGNAL DETECTOR (CF) - Modem control
bit 3. Held ON by the TIP, except for a short
(approximately 1/2 sec.) period following an ON
to OFF transition of DATA TERMINAL READY, during
which it goes off.
20 E8 DATA TERMINAL READY (CD) - Modem status bit 2.
THIS SIGNAL IS USED BY THE TIP to determine that
the terminal is connected to the TIP. If "hunt"
mode is enabled for this device, an ON to OFF
transition of this signal initiates "hunt" mode.
The following control signals are held on by the TIP
software:
5 E4 CLEAR TO SEND (CB) - Modem control bit 0. Held
ON by the TIP.
6 E19 DATA SET READY (CC) - Modem control bit 2. Held
ON by the TIP.
16 E14 SECONDARY RECEIVED DATA (SBB) - Modem control bit
1. Held ON by the TIP.
The following status signals are ignored by the TIP
software:
4 E5 REQUEST TO SEND (CA) - Modem status bit 0.
Ignored by the TIP.
12 E12 SECONDARY RECEIVED LINE SIGNAL DETECTOR (SCF) -
Modem status bit 3. Ignored by the TIP.
13 E13 SECONDARY CLEAR TO SEND (SCB) - Modem status bit
4. Ignored by the TIP.
14 E16 SECONDARY TRANSMITTED DATA (SBA) - Modem status
bit 5. Ignored by the TIP.
19 E6 SECONDARY REQUEST TO SEND (SCA) - Modem status bit
1. Ignored by the TIP.
*This configuration makes the LIU look approximately like a 103
modem to the terminal.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
C. Modems
It is desired that the TIP be able to operate with terminals over
private or leased lines, or over the switched telephone network. This
requires the use of a pair of modems between the terminal and the TIP.
The TIP basically supports the Bell 103 class of modems. An extension
is the Vadic 3400 which is 1200 baud full duplex with 103 protocol. A
202 equivalent modem is being used in Simplex mode to drive a remote
line printer.
It may be that a group desiring to use another type of modem
could coax that modem to work within the available software and
hardware structure. For that purpose, this section will try to
describe the difficulties in using half-duplex modems, the use of
synchronous modems, and the manner in which the 103 modem is
supported.
Half-Duplex Modems
Half-duplex modems are modems in which data on the primary data
channel can flow in only one direction at a time. Data cannot flow
both ways at the same time. There may or may not be a "secondary" or
"supervisory" channel which points in the direction opposite the
primary channel. The essential problem involved in half-duplex
operation is control of the direction of data flow on the primary
channel. Significant questions are:
- What protocol should be adopted for turning the line
around -- special control characters, or use of a
secondary channel?
- Which end (if either) is in control of the channel?
- If the terminal is receiving a large listing, how
can the user terminate the output when the channel
is pointing the wrong way?
- Who should do the echoing and when?
These problems are clearly a matter of convention.
Unfortunately, EIA Standard RS-232, which many modems follow, does not
define a convention which would answer these questions. It is very
helpful if a request to BBN for a modem on the TIP includes a
statement of what terminals are to be connected to the other end, and
what convention they follow.
Synchronous Modems
The TIP should be able to use synchronous modems provided that
the characters are framed by start and stop bits, and that the
synchronous modem is similar enough to a modem which is supported by
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
the software. The device rate must be set to external clock mode
through the use of a TIP command such as:
@ DEVICE RATE 1023
103 Modems
Description:
The Bell Telephone 103 modem is a low-speed (up to 300 baud),
asynchronous, full-duplex modem for use on private leased lines or the
switched telephone network.
Connection:
See Table 9-2 for the pin connection on the LIU card, and for a
description of the TIP's use of the signals.
Operation:
In use, the modem at the TIP end is usually left in the
AUTO-ANSWER mode. When a user wishes to connect his terminal, he
dials the number of the modem at the TIP. After the ring is answered
and a data carrier is heard, the user depresses the DATA button. The
user is then connected as if his terminal were connected directly to
the TIP. He types the characteristic character for his terminal,
receives the header message, and proceeds to use the network as
desired.
Simplex Modem Connections
A simplex modem connection is defined as a modem connected to an
LIU card with data flowing in one direction only. Its primary use is
to connect a line printer at a remote site to a TIP. A 1200 baud
asynchronous modem (with supervisory reverse channel) is usually used.
Any modem will probably work including half duplex types. Since the
half duplex protocol is to have the called modem transmit first,
simplex should work quite well.
The LIU will hold EIA pins 3 and 11 at ground. There are
normally not enough pads on the pin 3 patch panel, so a minor change
to the LIU card and a jumper must be prepared. If this connection is
desired, call the NCC for further information and assistance.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
TABLE 9-2
TIP SIGNAL ALLOCATION FOR 103 MODEM
EIA LIU
PIN PAD
1 E1 PROTECTIVE GROUND (AA) - Used.
2 E2 TRANSMITTED DATA (BA) - Used for data going from
the TIP to the MODEM.
3 E3 RECEIVED DATA (BB) - Used for data going from the
MODEM to the TIP.
5 E5 CLEAR TO SEND (CB) - Modem status bit 0. Ignored
by the TIP.
6 E6 DATA SET READY (CC) - Modem status bit 1. Used
in conjunction with CF to determine whether a
legitimate data call has been made or whether the
connection should be terminated.
7 E7 SIGNAL GROUND (AB) - Used.
8 E8 RECEIVED LINE SIGNAL DETECTOR (CF) = modem status
bit 2. This signal is used by the TIP to
determine that a connection has been made. If
"hunt" mode is enabled for this device, an ON
to OFF transition initiates "hunt" mode.
20 E20 DATA TERMINAL READY (CD) - Modem control bit 3.
Held ON by the TIP, except for a short
(approximately 1/2 sec.) period after TIP
software decides whether a legitimate data call
has been made or whether the connection should be
terminated.
All other signals are connected as shown in Appendix A
but are not used by the 103 modem.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
Table 9-3
LIU Patch Panel Configurations
EIA 103 STD MDL37 SIMPLEX 202
PIN MODEM TERMINAL TTY MODEM* MODEM
1 1 1 1 1 1
2 2 3 3 2 2
3 3 2 2 OPEN 3
4 4 5 5 4 4
5 5 4 4 5 5
6 6 19 8 6 6
7 7 7 7 7,3 7
8 8 20 20 12 8
9 - - - - -
10 - - - - -
11 11 11 11 7 14
12 12 12 12 8 16
13 13 13 13 13 13
14 14 16 16 14 12
15 15 17 17 15 15
16 16 14 14 16 11
17 17 15 15 17 17
18 - - - - -
19 19 6 6 19 19
20 20 8 8 20 20
21 - - - - -
22 -
23 - - - - -
24 24 25 25 24 24
25 25 24 24 25 25
Labels (M,103, (T) (37) (SM) (202)
or None)
*A jumper and a minor change to the LIU card is
needed for this configuration.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
APPENDIX A: HOST ADDRESSES
The following is a table of Hosts on the Network at the time this
update was published. The columns (from left to right) are: Octal
Host address, Decimal Host address, Host name, (Interface computer, if
any, and) computer type, Status of the system and type of operating
system.
Host Address Hostname (Interface)-> Status/
Octal Decimal Computer System
-------------------------------------------------------------------
001 1 UCLA-ATS PDP-11/45 User
ANTS, ELF
101 65 UCLA-CCN IBM 360/91 Server
TSO, OS-MVT
201 129 UCLA-CCBS (PDP-15)-> limited Server
PDP-10 DEC 10/50
002 2 ARC-RD PDP-11/40 User
ELF
102 66 SRI-AI (PDP-10)-> limited Server
PDP-15 TENEX
202 130 SRI-ARC PDP-11/40 User
ELF
003 3 UCSB-MOD75 IBM 360/75 Server
OLS, OS-MVT
203 131 CHII (VDH)-> Server
Signal-1
004 4 UTAH-10 PDP-10 limited Server
TENEX
204 132 UTAH-TIP TIP
105 69 BBN-11X PDP-11 Server
ELF
205 133 BBN-11XB PDP-11 User
ELF
305 197 BBN-TENEXA PDP-10 limited Server
TENEX
006 6 MIT-DEVMULTICS H-68/80 User
Multics
106 70 MIT-DMS PDP-10 Server
ITS
206 134 MIT-AI PDP-10 limited Server
ITS
306 198 MIT-ML PDP-10 Server
ITS
007 7 RAND-RCC IBM 370/158 Server
OS-MVT
107 71 RAND-ISD PDP-11/45 Server
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
UNIX
010 8 SDC-LAB IBM 370/145 limited Server
SDC-VM
110 72 SDC-CC IBM 370/158 Server
VS2
011 9 HARV-10 PDP-10 limited Server
DEC 10/50
111 73 HARV-1 PDP-1 User
311 201 HASKINS (VDH)-> User
PDP-11/45 ELF, RSX-11D
012 10 LL IBM 370/168 limited Server
VM-370
212 138 LL-TSP TSP User
312 202 LL-11 (PDP-11/45)-> User
SPS-41 ELF, RSX-11M
013 11 SU-AI PDP-10 Server
DEC 10/50
113 75 SU-DSL (VDH)-> User
PDP-11/20 ELF
014 12 ILL-CAC PDP-11/20 User
ANTS
114 76 ILL-NTS PDP-11/50 User
UNIX
214 140 UNIVAC (VDH)-> User
(UNIVAC 1218)->
UNIVAC 1616
015 13 GUNTER (PDP-11/35)-> User
B4700 (ELF) MCPV
016 14 CMU-10B PDP-10 Server
DEC 10/50
116 78 CMU-10A PDP-10 limited Server
DEC 10/50
216 142 CMU-11 C.mmp Summer '75
Hydra
316 206 CMU-CC (PDP-11)-> Summer '75
IBM 360/67 + UNIVAC 1108
017 15 I4A-TENEX (PDP-10)-> Server
ILLIAC IV + B6700 (TENEX)
117 79 I4-ELF (PDP-11)-> Server
ILLIAC IV (ELF)
217 143 I4B-TENEX (PDP-10)-> limited Server
ILLIAC IV (TENEX)
020 16 AMES-67 IBM 360/67 Server
TSS/360
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
220 144 AMES-TIP TIP
320 208 AMES-11 (PDP-11/45)-> User
CDC 7600
221 145 MITRE-TIP TIP
022 18 RADC-MULTICS H-6180 User
Multics
222 146 RADC-TIP TIP
023 19 NBS-ICST PDP-11/45 + PDP-10 Not Active.
223 147 NBS-TIP TIP
024 20 ETAC (PDP-11/45)-> Summer '75
CDC-6600 (ANTS)
224 148 ETAC-TIP TIP
025 21 LLL-RISOS PDP-11/45 limited Server
RATS
026 22 ISI-SPEECH11 (PDP-11/45)-> User
SPS-41 ELF, DOS
126 86 USC-ISI PDP-10 Server
TENEX
226 150 USC-ISIB PDP-10 limited Server
TENEX
326 214 ISI-XPG11 PDP-11/40 User
ELF
027 23 USC-44 IBM 360/44 Server
USC-PS
227 151 USC-TIP TIP
327 215 USC-ECL PDP-10 Server
TENEX
230 152 GWC-TIP TIP
231 153 DOCB-TIP TIP
032 26 SDAC-44 IBM 360/44 limited Server
DOS/360, USC-PS
232 154 SDAC-TIP TIP
332 218 SDAC-CCP BBN-Pluribus alternate to
#39 decimal
033 27 BELVOIR (PDP-11)-> User
CDC 6600 (ANTS) Scope
034 28 ARPA-DMS PDP-15 limited Server
Keydata DMS
234 156 ARPA-TIP TIP
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
035 29 BRL PDP-11/40 User
ANTS
236 158 BBN-TESTIP TIP
037 31 CCA-TENEX (PDP-10)-> dedicated Server
Datacomputer TENEX,Datacomputer
137 95 LL-ASG (VDH)-> User
PDP-11/50 ELF
237 159 CCA-TIP TIP
337 223 CCA-SIP PDP-11/40 User
ELF
040 32 PARC-MAXC (Nova)-> limited Server
MAXC TENEX
140 96 PARC-VTS Nova 800 User
VTS
041 33 FNWC (CDC 3200)-> Not Active
CDC 6500 SCOPE
241 161 FNWC-TIP TIP
042 34 LBL (CDC 6600)-> Server
CDC 7600 (Sesame) BKY
142 98 UCB (VDH)-> User
PDP-11/45 ELF, DOS
043 35 UCSD-CC (Micro 810)-> Server
B6700 MCP
044 36 HAWAII-ALOHA HP 2100 User
Menehune
244 164 ALOHA-TIP TIP
344 228 HAWAII-500 (PDP-11)-> limited Server
BCC 500 (ELF) BKY OpSys
045 37 RML-7 Sigma 7 User
BPS
245 165 RML-TIP TIP
046 38 PURDUE PDP-11/45 User
ANTS
047 39 SDAC-CCP BBN-Pluribus User
147 103 SDAC-DP IBM 360/40 User
DOS/360
247 167 SDAC-NEP IBM 360/40 User
DOS/360
050 40 BBN-NCC H-316 User
250 168 NCC-TIP TIP
350 232 BBN-1D PDP-1 User
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
051 41 NORSAR-40B IBM 360/40 Fall '75
DOS/360
251 169 NORSAR-TIP TIP
351 233 NORSAR-40A IBM 360/40 Fall '75
DOS/360
052 42 LONDON (PDP-9)-> limited Server
IBM 360/195 OS/MVT ?
152 106 LONDON-VDH (VDH)-> User
(PDP-9)-> CMAS
ATLAS II
252 170 LONDON-TIP TIP
053 43 OFFICE-1 PDP-10 dedicated Server
TENEX,NLS
253 171 TYMSHARE-TIP TIP
054 44 MIT-MULTICS H-6180 Server
Multics
055 45 SCI-TENEX PDP-10 limited Server
056 46 RUTGERS-10 PDP-10/70 Server
TOPS-10
156 110 ADR (VDH)-> User
PDP-11 ELF
256 174 RUTGERS-TIP TIP
257 175 WPAFB-TIP TIP
160 112 ASL (VDH)-> User
PDP-11/10 ELF
260 176 AFWL-TIP TIP
061 49 BBN-TENEXB PDP-10 limited Server
TENEX
161 113 BBN-SAT (VDH)-> User
PDP-11/40 ELF, RT-11
261 177 BBN10X-TIP TIP
361 241 BBN-TENEX PDP-10 Server
TENEX
062 50 BBN-SPEECH-11 (PDP-11/40)-> Summer '75
SPS-41 ELF
162 114 BBN-TENEXD PDP-10 limited Server
TENEX
063 51 SRI-NSC11 (PDP-11/40)-> User
SPS-41 ELF, DOS
163 115 SRI-IA11 PDP-11/40 User
RSX-11M
263 179 SRI-CBC11 PDP-11/10 User
363 243 SRI-PKT PDP-11 Summer '75
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
264 180 ISI-TIP TIP
364 244 USC-ISIC PDP-10 Server
TENEX
065 53 EGLIN CDC 6600 User
SCOPE
066 54 SCRL-ELFDEVEL PDP-11/20 User
ELF
166 118 SCRL-ELF (VDH)-> User
PDP-11/45 ELF
067 55 ANL (VARIAN-73)-> Server
IBM 370/195 OS-MVT
070 56 SUMEX-AIM PDP-10 Server
TENEX
071 57 NSA PDP-10 Fall '75
TENEX
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
APPENDIX B: COMMAND SUMMARY*
Section
BINARY INPUT END
Leave 8-bit binary input mode 5-C
BINARY INPUT START
Enter 8-bit binary input mode 5-C
BINARY OUTPUT END
Leave 8-bit binary output mode 5-C
BINARY OUTPUT START
Enter 8-bit binary output mode 5-C
CLEAR DEVICE WILD
Set device to be unwild 5-G
CLEAR INSERT LINEFEED
Stop inserting linefeed after carriage-return 4-B
CLOSE
Close all outstanding connections, or abort current Host
login 4-D
DEVICE CODE 37
Establish parity computation for Model 37 Teletype 5-A
DEVICE CODE ASCII
Establish code conversion for an ASCII terminal 5-A
DEVICE CODE EXTRA-PADDING
Establish code conversion for a terminal with slow CR 5-A
DEVICE CODE OTHER-PADDING
Establish code conversion for a line printer 5-A
DEVICE RATE #
# is a 10-bit code specifying hardware rate and 5-A
character size settings
# DIVERT OUTPUT
Capture device # and divert this terminal's output 5-E
to it. # is an octal number.
ECHO ALL
Local TIP-generated echo -- TIP echoes everything 4-B
---------------
* # denotes a decimal number unless otherwise stated
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
ECHO HALFDUPLEX
Terminal-generated echo -- TIP echoes nothing 4-B
ECHO LOCAL
Send the Telnet "ECHO LOCAL" character and 4-B
perform internal E A
ECHO NONE
Remote Host-generated echo for data -- 4-B
TIP echoes commands
ECHO REMOTE
Send the Telnet "ECHO REMOTE" character and 4-B
perform internal E N
FLUSH
Delete all characters in input buffer 5-F
# GIVE BACK
Release control of captured device #. 5-D
# is an octal number.
HOST #
Simultaneous "@S T H" and "@R F H" 5-B
INITIAL CONNECTION PROTOCOL
Start the initial connection protocol 5-H
INSERT LINEFEED
Insert linefeed after carriage-returns 4-D
INTERCEPT #
Use # as TIP command character 4-D
INTERCEPT ESC 4-D
Leave 7-bit binary mode 5-C
INTERCEPT NONE 4-D
Enter 7-bit binary mode 5-C
LOGIN #
An obsolete form of OPEN
M # #
Mag tape command # with argument # 8
NETWORK-VIRTUAL-TIP-EXECUTIVE 4-F
Connects the user to the Network-Virtual-
TIP-Executive.
OPEN #
Open a bi-directional connection to the Host
decimal address is specified 4-C
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
PROTOCOL BOTH
Simultaneous "@P T T" and "@P T R" 5-B
PROTOCOL TO RECEIVE
Manually initiate connection protocol 5-B
PROTOCOL TO TRANSMIT
Manually initiate connection protocol 5-B
RECEIVE FROM HOST #
Establish Host # parameter for manual 5-B
initialization
RECEIVE FROM SOCKET #
Establish socket # parameter for manual 5-B
initialization of connection -- socket # is
given in octal
RECEIVE FROM WILD
Equivalent to "@R F S <any>" 5-G
RESET
Reset current TIP port parameters 5-J
Reset NCP
Resets NCP 5-H
SEND BREAK
Send the Telnet "BREAK" character 4-D
SEND COMMAND
Send the command escape character 5-I
SEND SYNC
Send the Telnet "SYNC" character and 4-D
an "INTERRUPT SENDER" message
SEND TO HOST #
Establish Host # parameter for manual 5-B
initialization of connection
SEND TO SOCKET #
Establish socket # parameter for manual 5-B
initialization of connection -- socket # is
given in octal
SEND TO WILD
Equivalent to "@S T S <any>" 5-G
SET DEVICE WILD
Equilvalent to the commands "@R F H <any>", 5-G
"@S T H <any>", "@S T S <any>", and "@R F S <any>".
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
TRANSMIT EVERY #
Send off input buffer at least every #th 4-B
character where 0<#<256
TRANSMIT NOW
Send off input buffer now 4-B
TRANSMIT ON LINEFEED
Send input buffer every time a linefeed is 4-B
encountered
TRANSMIT ON MESSAGE-END
Send input buffer every time an end-of-message 4-B
is encountered
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
APPENDIX C: BIBLIOGRAPHY
Most of the following should be available through your Network
Information Center Station Agent or the
ARPA Network Information Center
Augmentation Research Center
Stanford Research Institute
333 Ravenswood Avenue
Menlo Park, California 94025
Specifications for the Interconnection of a Host and an IMP, BBN
Report No. 1822 (IMP-HOST section of NIC 7104).
IMP Operating Manual, BBN Report No. 1877.
The Interface Message Processor for the ARPA Computer Network, Heart
et al, Proceedings AFIPS 1970 Spring Joint Computer Conference (NIC
4655).
The Network Working Group "Request for Comments" Series: A Set of
Working Papers on Host Protocol.
The Network Resource Notebook, NIC 6740.
The BBN Terminal Interface Message Processor (Hardware Manual), BBN
Report No. 2184.
Specifications for the Interconnection of Terminals and the Terminal
IMP, BBN Report 2277.
ARPA Network Current Network Protocols, NIC 7104.
The Terminal IMP for the ARPA Computer Network, Ornstein et al,
Proceedings AFIPS 1972 Spring Joint Computer Conference.
Terminal Access to the ARPA Network: Experience and Inprovements,
Mimno et al, COMPCON 73, Proceedings Seventh Annual IEEE Computer
Society International Conference, San Francisco, February 27 - March
1, 1973.
TIP Users Group Notes, a series of informal notes designed to increase
communication among the developers of the TIP, TIP users, and Hosts
frequently used from TIPs. To be put on the distribution list for
these notes, apply to the NIC Station Agent.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
APPENDIX D: TERMINALS USED WITH THE TIP
The following terminals are reputed to have worked with the TIP.
See the Introduction (Section 1).
A. B. DICK VIDEOJET 9600 LINE PRINTER (2400 bps)
ANDERSON-JACOBSON (models 630 and 841)
ARDS
KSR-35 Teletype
CALCOMP 565
CDI 1030/ "MULTICS" Terminal
DATA 100 (model 73)
DATAPOINT (models 2200, 3000, and 3300)
DELTA TELTERM 2
DIGITAL EQUIPMENT CORP. (models VT05 and GT40A)
EDT 1200
HAZELTINE 2000
LINEOLEX (model A)
MEMOREX 1240
SUGARMAN (model S-4300)
TECTRAN CASSETTE
TEKTRONICS (models 4010 and 4013)
TELETERM (model 1030)
TELETYPE (MODEL 38)
TERMINET 300
TI Silent 700
TYCOM
TRENDATA (model 1000)
UNIVAC DCT 500
VIDEO SYSTEMS (models 1200 and 5000)
We would be pleased to hear of any other terminals that have
operated on a TIP.
At the International Conference on Computer Communications held
in Washington, D.C., in October 1972, we had the opportunity to
personally test a number of the above terminals with the TIP. As a
result of this experience we now hold opinions as to the methods and
difficulty of connecting a number of these terminals to the TIP. We
suggest you call the Network Control Center to be put in touch with
someone about this subject.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
APPENDIX E: NEW TELNET PROTOCOL IMPLEMENTATION
The NEW TELNET protocol has been implemented in TIP systems
numbered greater than 350. Wherever possible, the TIP should appear
just the same to the user, but some differences do occur. Some
background information is perhaps useful. Both protocols are based on
the concept of the NETWORK VIRTUAL TERMINAL, as described in Section
2; each also defines TELNET commands that may be sent to instruct the
other side, for instance, concerning echo mode. In the OLD TELNET,
such commands are unequivocal demands, and cannot be refused even if
the state is undesirable. A Host can of course undo the state with a
counter command of its own, but it first must understand what has
happened; in addition, there is no guarantee that the same sequence
won't occur again. The NEW TELNET protocol defines a minimal default
set of parameters, then allows each side to negotiate for non-standard
options. No Host is required to accept an undesirable state; in fact,
a Host can simply refuse to do "whatever the other side requested" and
need not even understand what it has just refused. This protocol
should allow sophisticated Hosts to define complex options without
burdening simpler Hosts.
A direct implication to the TIP user is that a "command" is now a
"request" and may be refused. It is possible, for instance, to ask
for remote echoing (local echo is the default) and not get it. In
practice, systems provide the same, or increased, capabilities under
the new protocol.
On the positive side, the TIP now acts as an advocate for the
remote terminal user. In the case of a halfduplex terminal like the
2741, the TIP can refuse to accept the remote echo option and the user
no longer needs to cope with double echoing when the connection opens.
The NEW TELNET protocol specifically affects the following
aspects of the TIP.
A. Getting In and Out of NEW TELNET Mode
The commands @OLD TELNET and @NEW TELNET set the TIP to expect
OLD or NEW TELNET respectively. The default as of this writing is OLD
TELNET, and @RESET automatically returns the device to OLD TELNET for
all devices. This action also occurs when a non-permanent, that is,
hunting terminal, hunts to its correct rate.
The TIP saves this mode state for each device. When a command is
given, for say echo or binary, the TIP determines which protocol the
device is using and responds appropriately.
Report No. 2183 Bolt Beranek and Newman Inc.
March 1976 Revision
B. Echoing
The TIP echo commands have the same meaning in NEW TELNET as in
OLD TELNET, as revised above. In addition, the TIP now remembers the
mode that the user desires, even though it may not be possible to be
in that state at the time. If the command is given when a connection
is open, the effect is the same as OLD TELNET, with the TIP sending
the request to the remote Host. If, however, the command is given
while the connection is closed, the TIP will save the user's request
and send it to the remote Host automatically, each time a connection
opens.
Non-hunting terminals will continue to be pre-initialized as
arranged by the designated site representative and the Network Control
Center. Most hunting terminals will default to remote echo mode;
however, physical halfduplex terminals (2741s) will not accept remote
echoing ever, whether hunting or not.
C. Binary Input and Output Options
Binary input and/or binary output are available under the NEW
TELNET protocol. The commands are:
@ BINARY INPUT START begins binary input mode
@ BINARY INPUT END ends binary input mode
@ BINARY OUTPUT START begins binary output mode
@ BINARY OUTPUT END ends binary output mode
As with the echo option, the TIP sets an internal flag for the
mode the user wishes, and attempts to get the remote Host to agree.
This feature is not yet automatic: the TIP will not send a request
unless the connection is open at the time of the command, but the TIP
will passively accept a request for binary mode from a remote Host
until the user ends binary mode. This may be useful for paper tape
punches, for example.
D. Log or Open a Connection
The @ OPEN and @ LOG commands will automatically determine the
appropiate socket for the ICP and the TIP will interpret the correct
TELNET protocol.
NOTE: when connections are made directly (and not through the LOG
or OPEN commands), the user should take care to be in the proper
TELNET mode. An example might be a lineprinter or paper tape punch
set wild. Any program connecting to such devices must use the same
TELNET protocol that the device is set to.