Date: Mon, 24 Jul 1995 22:06:16 -0700 From: harry@hgac.com (Harry Goldschmitt) To: terry@cs.weber.edu (Terry Lambert) Cc: bde@zeta.org.au, hackers@freebsd.org, ache@astral.msk.su (=?KOI8-R?Q?=E1=CE=C4=D2=C5=CA_=FE=C5=D2=CE=CF=D7?= aka), jkh@violet.berkeley.edu, pas@tonesoft.com Subject: Re: dial up at > 9600 baud Message-ID: <v01530508ac3a2146b865@[199.107.69.186]>
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>> Terry, you seems to miss a bit of discussion: situation is >> pretty clear: modem inherits speed of previous access, if >> it isn't configured to reset by DTR drop. > >If the modem can't be correctly configured, get a new modem, or >build a curcuit that will actually power cycle the modem on DTR >on-to-off transition (a relatively trivial circuit). > I hate to butt in, most modern modems can be configured to a specific modem to modem connect speed (which we did), but I haven't seen one yet that can be configured for the modem to serial port speed! If you know of one, and can prove it works (not just theory), let me know. We tried three different modems, a 14.4 internal, a 28.8 internal and a 14.4 external, all from different companies. >If the modem can't be correctly configgured, I *STRONGLY* urge >replacing the modem. A Tandy DT1200 modem won't pass ^N characters, >and I would hardly suggest hacking all comm software to avoid ^N >to make the bogus modem happy. See above, and try it! >> It means that any dialout application which change speed >> becomes getty-killer. >> There is no error in the driver or in getty. >> Solution for it already exists: >> 1) Configure modem to gettytab speed and issue AT&W. >> 2) Configure modem to do ATZ on DTR drop. > >Yes yes yes. > No no no. That's not what's happening in our case. We boot up, use slattach at a speed of 38400, or whatever. It works at 38400. We kill slattach, configure etc/ttys so that the port is on, and do a kill -HUP 1. Guess what, dials to the port connect at 9600. Somewhere in the driver, characters like AT are being sent at 9600, which happens to be the ttydefaults.h setting. Not believing our eyes, we tried three different brands of modems, two internal and one external. Same symptoms. We then modified /etc/ttys back to turn the port off and kill init, yet again. We then restart slattach at 38400, everything is fine. We also tried the experiment with cu and tip. Every thing works but getty. Sounds to me like the getty-killer is getty! Does anyone have a 14.4 or 28.8 modem? Can you beg, borrow or steal one. If you don't think I'm telling the truth, try the above experiments! >> If we allow modem to not do ATZ on DTR drop, more complex >> things will be involved in driver and getty, namely: >> 1) Driver must issue "AT" command at first open >> to give modem chance to sense speed. > >No no no. The Modem is idiotically "sensing" the speed. This is >the problem in the first place. The driver should not "set" the >modem, especially when these commands aren't going to work on >non-AT command set modems that are otherwise non-bogus. > How about a Hayes compatible driver to set the modem. The modem can't possibly know the modem to serial port speed until it can autobaud via an AT command for Hayes. There is nothing in the RS-232 lines that can cause the modem to do much until some data is transmitted - Tx. I agree that the settings should be taken from the sio driver first, especiallly the lock device. But someone, somewhere will want to reset the speed for a particuar getty. On close, the port settings should probably be set back to the initial driver settings. Like I said, every application we tried worked properly, except getty. And it reset the port to ttydefaults. Harry Goldschmitt | harry@hgac.com 1226 Starlit Rd. | (714)494-6086 Laguna Beach, CA 92651-3035 | Fax:(714)494-3072
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