TELECOM Digest OnLine - Sorted: Re: History of Hayes Modem

Re: History of Hayes Modem
23 Jan 2006 07:14:46 -0800

Dave Thompson wrote:

> Paper-tape reader and punch control was an option of the Teletype, not
> the modem. It could be used even on direct connections.

That's true. I felt the original posting implied that Hayes invented
something entirely new; which wasn't quite true. The point I wanted
to make was that prior to the Hayes instruction set developed with
their modem, there already existed remote control options to control
terminal equipment. Yes, Hayes further automated and streamlined the
functionality, and moved some of it from the terminal equipment to the

One Hayes command -- automatically turning off the modem sound of
dialing and connection handshake -- resulted in fraud. PC terminals
would be sent a program that would do that and thus secretly be able
to dial anywhere, such as an extremely expensive overseas call to a
weird corrupt location.

In computer time sharing usage, most Teletypes used plain friction
feed platens. But they always offered a sprocket feed for pre-printed
business forms. You had to be more careful with those because a
control-VT (vertical tab) -- ignored on friction feed units -- would
cause a page eject on form feed units and you could inadvertently dump
a lot of paper on the floor.

When I transitioned from Teletype to computerized PC terminals, I was
disappointed that I lost the control tape-reader on/off functionality.
I had programs that would call for off-line prepared tapes, this
didn't transition over to computers without rewriting program. I
don't believe the telecom programs (Telix, Procomm) could do anything
with those control commands.

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