perm filename WIRING.PUB[CMG,ROB]1 blob sn#504356 filedate 1980-03-04 generic text, type C, neo UTF8
C00001 00001
C00002 00002	.require "[lib,rob]" source_file
C00003 00003	.skip 10
C00004 00004	.next page sec(Morass with less pain therein)
C00008 00005	.next page sec(The TelCo stuff)
C00011 00006	.next page sec(The Video stuff)
C00013 00007	.next page sec(the bottom line)
C00016 ENDMK
.require "[lib,rob]" source_file;
.every heading(,|{ital(Building Wiring for CCRMA)}|,{DATE})
.every footing(,|Page {PAGE}|,)
.place text;
.next page;
.skip 10
.begin "intro"
.narrow 10
As I was passing Project MAC,
I met a Quux with seven hacks.
Every hack had seven bugs;
Every bug had seven manifestations;
Every manifestation had seven symptoms.
Symptoms, manifestations, bugs, and hacks,
How many losses at Project MAC?

                -- TGQ April 27, 1974
{tiny(|[ (c) Copyright 1974 Guy L. Steele Jr.  All rights reserved.]|)}
.end "intro";
.next page; sec(Morass with less pain therein)

We have bunches of devices to interconnect.  We have offices stations.
Each station has a 25-pair shieleded cable and
an RG-59 video cable.  We have a Foonly F2 computer, with a teletype scanner.  The
scanner has sixteen (perhaps 32) teletype lines.  Each teletype line
requires eight wires for full control.  We have a UDS modem rack, with
slots for 16 modems.  We have a Grinnel video display system with twelve
video outputs.  We have an audio switching and routing system with an
as yet unspecified number of inputs and outputs, but the general dimensions
will probably be something like 32 in and 64 out.

The point of this is that all of these devices have to get connected to
each other.  So, what is a {ital(connection)}?  A connection is a
{ital(logical)} association of two (or more) {ital(physical)} devices.
What we need is a cheap and simple system for making these connections.
It is desirable to end up with a system that makes it easy to answer such
questions as "Where does this teletype line connect to?"  or "How can I
connect the tape deck in my office to the audio switch?".

.sec(How it goes together)

I propose that we use the strategies that were adopted for the building
wiring at Margaret Jacks Hall.  There are the same sorts of problems in
MJH ,though thies are on a larger scale (about 200 office stations, five
computer systems, many dial-up lines, etc).  

For "com wiring" in MJH, the wire used and the
interconnection blocks are the same as used by the telephone company.  The
stuff that the phone company uses is noted for being truly inexpensive,
and always available from several vendors.  It is a well debugged
technology, that is, it is easy to work with, and the resulting
interconnections are reliable.

All of the video signals in MJH are routed RG-59 video coax with standard BNC connectors.
Patching is done on "video brackets" which they had fabricated for the
purpose.  Each bracket mounts on the wall and holds ten female BNC connectors.

At CCRMA, I suggest that all of the
connector panels (this includes both the punch-down blocks as
well as the video connector brackets) appear in one logical place.
Each physical device would appear on a connector panel (or panels, as
the case may be).  The devices include the Foonly TTY scanner, the Audio
Switch inputs and outputs, the office stations, the UDS modem connections,
the Grinnel display system, and anything else we might dream up.

.next page; sec(The TelCo stuff)
Here is a list of the basic things used in this system.  Everything here
is stocked by several vendors, and is an excellent deal for the money.
We may even have some of these items
ourselves (if we search the building harder
than we search our consciousness).

.sec(25 pair wire)
This is very cheap, readily available, color coded, easy to strip, and
adapted to this technology.

.sec(punch-down blocks)
Each of these punch down blocks will terminate one or two 25 pair wires
(depending on the style we get).

.sec(50-pin to punch-down connectors)
These accept a 50-pin TelCo style "blue ribbon" connector and bring all
of its wires out to a punch down block.  These are useful for things that
already have the 50-pin connectors on them (like the UDS modems).  In fact,
there is a TelCo regulation that requires DAA devices to have some sort of
un-pluggable connector.

.sec(back panels)
These screw onto the wall, and have holes in the right places to mount the
punch-down blocks.

These mount the punch-down blocks onto the mounting panels

.sec(guide posts)
In the grubby detail department, these are plastic spool-like devices
that screw onto the wall and give you something to route wires around.

.sec(punch-down tool)
This is a little hand held frob.  You need it to connect the wires to
the punch down blocks (it cuts the wire off as it make the connection).
Once you get the hang of it, connecting an entire block goes very quickly.

.next page; sec(The Video stuff)
This is a list of the stuff used to route the video signals around.
.sec(The cable)
Most of the building is already wired with RG-59 video coax.  Any new
wiring should probably follow suit.

.sec(The connectors)
Connectors throughout will be standard BNC crimp connectors.  If my memory
serves me correctly, CCRMA already has a bunch of these (as well as the
crimping tool), though we may have to buy some female chassis-mount BNCs.

.sec(The connector brackets)
The folks at MJH have already made up a bunch of BNC connector brackets for
their own use.
Each bracket holds 10 female chassis-mount BNC connectors.
They have some extras, and indicate that CCRMA could buy some.

.next page; sec(the bottom line)

Here is a list of the essentials to this system.  We could get a
bit fancier with cosmetics, but that will probably have to wait until
we get the next Big Grant.

.sec(the com wiring)

.begin "table"
.tabs 8,20,44,52
.turn on "\"
.select 5	; comment FIX25;
.skip 2

50	\66M-150	\punch down blocks    \  5.25	\262.50
25	\		\distibuting posts    \  0.37	\  9.25
1000'	\		\25 pair telco wire   \200.00	\200.00
1	\Dracon		\punch down tool      \ 19.50	\ 19.50
1 pack	\ty-wrap	\wire dress thingies  \ 23.30	\ 23.30
	\		\			\	\------
	\		\			\	\514.75

.end "table"

These things are available from Nevada Wester, 350 Benardo Avenue,
Mountain View, Ca, 94043.  Our contact there is John Moore at

.sec (the video wiring)

The above doesn't yet include figures for the video wiring.  I don't
have pricing yet on that, but rough estimates suggest something
well under $300.


We will also need an acceptable thing to mount these blocks on.
A couple of sheets of plywood should do the trick, which we can
probably find around the lab somewhere.  if not, add about $25
to the above price.