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

Re: History of Hayes Modem

Reed (
Wed, 25 Jan 2006 02:47:17 GMT

John Levine wrote:

>> That's true. I felt the original posting implied that Hayes invented
>> something entirely new; which wasn't quite true.

> As far as I know, his was the first modem to use in-band signalling.
> It was really rather clever to build a UART into the modem and use it
> to let the computer control the modem over the same channel as it used
> to communicate with the remote system.

> In-band signalling has its problems (that's what made blue boxes
> possible) but in this case it let people hook up modems to their PCs
> using a cheap generic serial interface.

> R's,

> John

Dial modems that accepted dialing commands over the RS232 interface
did exist prior to Hayes (Codex and Vadic at least). What Hayes did
was improve the concept and patent the +++ escape sequence in
1985. Most prior modems could not go back to command mode without
disconnecting from the call, using "Long Space" disconnect. Also he
targeted the then-new PC market with a low cost unit. Codex etc were
considered corporate business-class modems priced accordingly.


Post Followup Article Use your browser's quoting feature to quote article into reply
Go to Next message: Henry Cabot Henhouse III: "Re: Verizon Launches FiOS TV in Massapequa Park; First Rollout in NY"
Go to Previous message: Lisa Hancock: "Re: Information Wants to be Free"
May be in reply to: The Great Idea Finder: "History of Hayes Modem"
Next in thread: Jeff Sutter: "Re: History of Hayes Modem"
TELECOM Digest: Home Page