Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!mit-eddie!bacchus!husc6!seismo!nbires!hao!gaia!zhahai From: zhahai@gaia.UUCP Newsgroups: comp.dcom.modems Subject: Re: Hayes command set oversight/problem Message-ID: <285@gaia.UUCP> Date: Sun, 15-Feb-87 19:09:17 EST Article-I.D.: gaia.285 Posted: Sun Feb 15 19:09:17 1987 Date-Received: Mon, 16-Feb-87 07:03:18 EST References: <871@basser.oz> Reply-To: zhahai@gaia.UUCP (Zhahai Stewart) Organization: Gaia Corp., Boulder, CO Lines: 80 In article <871@basser.oz> alans@basser.oz (Alan Skea) writes: >I originate a call to another machine which answers the call using a >similar "Hayes-Compatible" modem. >[to escape to the modem command mode] I type the usual +++ >delimited with the appropriate pauses. Now, MY modem, not knowing that >this is intended as a command for it until the final delimiting pause, >transmits this down the line to the other machine. MY modem then goes >into command mode. Now, here's the crunch; the machine at the other end >echoes my +++ and puts the remote modem into command mode. This is >clearly not desirable as there is no way to put the remote modem back >on-line. > > One solution to the problem >would be to change the escape character from + to, say, - on the >answering machine, but in order for this to be effective, everyone must >do the same thing. > >Proposal: > The modem in ORIGINATE mode will use the '+' as an escape character. > > The modem in ANSWER mode will use the '-' as the escape character, > if commands are enabled at all. Not a bad idea, but it is too late to make it a very useful standard inside the modem, as it would make the modem non-hayes compatible. Of course, one could create yet another extension to the Hayes command set, but then the software setting up the port for auto-answer would have to be changed to invoke this new not-quite-hayes mode; in which case, the software could just initialize the S2 register with current Hayes-compatible modems while awaiting a call (this changes the escape character, "+" by default), and then change it back before calling out. So, if you can influence or control the software at the "other end", you could with current modems achieve just what you wanted (+ for your modem, - for the remote modem). In fact some systems disable the escape entirely when going into auto-answer mode, by setting S2 to 0; you are not using one of those systems or you would never have had this problem. Again it is probably too late to do much for most of the "other ends" out there. Which brings us to YOUR end. If you modify your proposal to change your own modem escape character to something else (-, ^G, %, `, whatever), then use that to escape to your own modem (preceded and followed by pauses, of course), you should be home free - Unless the other end has changed their escape character to the same thing, which is unlikely. I hope this will solve your problem. If you are using a terminal emulation program on a computer, and it has commands which use the modem escape (for example, some programs send +++ATH0 to hang up the line), you may need to customize it for your new escape sequence. If your system also auto-answers, you can change the escape back to + after each callout. Or you can change it to something else so as not to catch other user's +++ sequences, in case they did not have the insight to change their escape chars for outgoing calls. So if a standard proposal is needed (which I am not sure about), it should change both the sending AND receiving escape characters. Switch to the sending escape before dialling out, switch back to the receiving code before re-enabling auto-answer after terminating the callout. This way you can escape even when calling a system which does not follow the "standard", and people calling your system can escape even if they dont follow the standard. Dial command: ATS2=45 ATD9999999