Date: Tue, 25 Jul 1995 15:28:43 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: harry@hgac.com (Harry Goldschmitt) Cc: terry@cs.weber.edu, bde@zeta.org.au, hackers@freebsd.org, ache@astral.msk.su, jkh@violet.berkeley.edu, pas@tonesoft.com Subject: Re: dial up at > 9600 baud Message-ID: <199507250558.PAA01884@genesis.atrad.adelaide.edu.au> In-Reply-To: <v01530508ac3a2146b865@[199.107.69.186]> from "Harry Goldschmitt" at Jul 24, 95 10:06:16 pm
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Harry Goldschmitt stands accused of saying: > 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. There are plenty that can be locked to a fixed DTE speed; I name most Interlink modems, as well as many Dataplex models as just two examples. > 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 Then your configuration is at fault. Getty should send _nothing_ until it sees DCD on the port. Try snooping the port with a terminal and see whether anything is getting dribbled. > 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! I and a number of local ISPs run 14K dialins supporting both user logins and SLIP without any such trouble. Are your /etc/ttys entries using getty.std or getty.38400? > 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. Nonononono. This is braindeath. Any halfway worthwhile modem can be hardwired to a fixed DTE rate, or will remember the last DTE rate across a power-cycle. The modem should realistically assume that the DTE rate on the serial port is that to which is has been set, and any failure on the part of the serial port to maintain its end of this expectation can be considered to be broken. Having observed (and indeed depended upon) this expectation functioning countless times, I can happily say that it's a Good Thing. > Harry Goldschmitt | harry@hgac.com -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" - Terry Lambert [[
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