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

Re: History of Hayes Modem

Robert Bonomi (
Wed, 11 Jan 2006 15:41:47 -0000

In article <>,
Justa Lurker <> wrote:

> Scott Dorsey wrote:

>> The Great Idea Finder <> wrote:

>>> Dennis C. Hayes invented the PC modem in 1977, establishing the
>>> critical technology that allowed today's online and Internet
>>> industries to emerge and grow.

>> Well, THERE is some pretty impressive revisionism. Hey, by 1977 there
>> were even kits like the Pennywhistle aimed directly at the
>> microcomputer community. --scott

> Yes, but wasn't a key difference between the two that the early modems
> like the Pennywhistle, etc. were more or less totally transparent to
> the data stream and the connection had to be manually dialed on a
> separate phone's keypad, the user had to listen for an answer tone
> before hitting "connect", manually disconnected at the end of the
> call, etc. while the Hayes modem was the first popular mass-market
> modem which also featured the escape sequence (+++), AT commands, call
> progress tone detection, etc.? The latter capabilities would put all
> modem operations truly under program control without need for any
> "hands-on" manual operation or intervention.

Modems had been in existance for around TWENTY YEARS, when Hayes built
their first 'smartmodem'.

"Autodial" and limited 'call progress' detection had been available
for more than a decade, as well. There was even a 'Bell Standard' for
the interface for the autodialer. (the Bell 801 automatic calling

Hayes _did_ invent the "AT" command set, and the '+++' escape
sequence. In fact, they own the *patent* on the guard-time-protected
excape sequence.

There _were_ other modem manufacturers who used 'in band' signalling
(as distinct from the out-of-band signaling used by a Bell 801 ACU)
for dialing commands, etc., prior to Hayes -- RACAL-VADIC was one.

The Hayes 'better moustrap' consisted of:

(1) using pure 'plain ASCII' for all operations,
(2) being able to exert complete control over the modem, *without*
having to manipulate the RS-232 'control' signals/pins.
(3) being able to 'escape' from data-transfer mode to modem control mode
(and return to data mode) *without* interrupting the modem-modem

They were not 'there first'.
They were not 'best'.
They were not 'fastest'.
They were not 'least expensive'.

Hayes modems sold for all the 'typical' reasons -- they delivered more
features (and/or 'easier to use' features) at a lower price-point than
the competition.

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