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From: tmb@ai.mit.edu (Thomas M. Breuel)
Newsgroups: gnu.misc.discuss,comp.dcom.modems,comp.misc
Subject: Hayes suit (timed escape sequence)
Message-ID: <13151@life.ai.mit.edu>
Date: 3 Feb 91 15:58:13 GMT
Reply-To: tmb@ai.mit.edu
Followup-To: comp.dcom.modems
Distribution: na
Organization: MIT Artificial Intelligence Lab
Lines: 34

|From: tnixon@hayes.uucp
|One such 
|patent is the Heatherington '302 patent, "Modem with Improved Escape 
|Sequence", which relates to the guard time associated with the "+++" 
|escape sequence used to change the modem from online to command 
|state.
|[Hayes has filed a patent infringement suit against several other
|modem manufacturers and won. This could mean that several low-cost
|modems become significantly more expensive, or some low-cost modem
|manufacturers go out of business.]

It seems to me that this patent might be invalid because of "prior
art". For example, several text editors use "guard times" to
distinguish the use of the ESC key by the user from the use of a
function key that generates an ESC sequence; in fact, in "vi",
depressing the ESC key (with guard time) switches from input to
command mode, whereas function keys don't. Double clicking with
a mouse is another example of the same principle.

The idea is so obvious that I am sure there are even earlier uses of
it, before the filing of the Hayes patent. If you can think of any
(old) software, device, or system, that uses this technique, it would
be nice if you could let the world know about it. The device
would probably not even have to be computer related: any device where
pushing a certain button several times in rapid succession overrides
its usual function could be of interest.

Please post replies to comp.dcom.modems.

						Thomas.

PS: I have no connection with either Hayes or any of the companies
sued by Hayes. I simply don't want to pay more for my modems because
of some patent that I believe may be invalid.