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←Communicating by DIALNET
←%3John McCarthy and Les Earnest
←%2Computer Science Department
←Stanford University
.end
%2Dialnet%1 is a project at Stanford University to give users
of a time-shared computer the ability to communicate with any other
computer in the world by ordinary telephone.  

Three main kinds of services are planned.  First, a user of one
computer, sitting at his terminal, can type a message and have it sent
to a user of another computer or even to a list of users of many
computers.  He may have the message sent right away or ask his computer
to wait for low night telephone rates.  When the intended recipient next
activates a terminal on his own computer, he is told about the message and
can read it when convenient.  Second, a user of one computer
can ask to have a file of information transferred to or from another
computer.  This speeds up the exchange of reports of all
kinds, data files, and computer programs.  Third, a user of one computer
can ask to have his terminal "connected" as a %2virtual terminal%1 to another
computer so that he can use its services.  All these particular
services are realized by letting a program in one
computer "telephone" a program in another computer and communicate
with it.  Of course, the called computer can refuse to perform any service its
owners haven't authorized.

In order to provide %2Dialnet%1 services to its users, a computer needs
a computer-controlled telephone dialer and
a device called a %2modem%1 for translating information to and from a form
suitable for telephone transmission.  The computer must also have
programs to interpret control messages from other computers
and initiate control messages of its own.  These messages must
conform to a standard or %2protocol%1 so that all computers will
understand how to handle them.  The
Stanford University project will develop and test such standard %2protocols%1.

Computer networks already exist providing such services, the most
famous being the U.S. Defense Department's ARPAnet.  However, these
networks require expensive special communication computers, use
expensive special communication lines, and involve substantial politics
and/or expense in joining the network.  There is also much telephone
communication between pairs of computers that have made special
arrangements with each other.  %2Dialnet%1 communication,
on the other hand, can be done by any computer
equipped with a dialer and modem (costing less than α$1,000) and which
implements the %2Dialnet%1 protocols.  Once this is done, its users
can communicate with any other %2Dialnet%1 computer in the world just
as anyone can telephone anyone else in the world.
Present telephone rates make transmission of messages and files quite
economical, but long distance %2virtual terminals%1 will be too
expensive for routine use.  Special networks can be more economical
for that, because they can conduct many dialogs over the same telephone
lines.

Work on this project began in July 1977 under sponsorship of the National
Science Foundation.
Preliminary Dialnet protocols will be available early in 1978 and a more
polished version is targeted for the end of 1978.  People interested in
implementing or influencing the protocols should write to %2Dialnet%1,
Artificial Intelligence Laboratory, Stanford, CA 94305.