Date: Mon, 11 Nov 1996 17:18:05 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: john@starfire.mn.org Cc: jgreco@brasil.moneng.mei.com, neal@pernet.net, freebsd-isp@freebsd.org Subject: Re: modems for dial-in/dial-out on FreeBSD(UNIX) (was: PPP/LCP sensing getty) Message-ID: <199611112318.RAA20128@brasil.moneng.mei.com> In-Reply-To: <199611112230.QAA16305@starfire.mn.org> from "john@starfire.mn.org" at Nov 11, 96 04:30:36 pm
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> This discussion has generalized beyond PPP/LCP now -- this information > is generally useful to anyone supporting dial-in connections, and > especially those sharing modems and lines for in and out. In fact, > Joe and I ought to prepare something on this for the FAQ, I suspect! I guess I have the experience :-( I was really into modems and stuff back in Commodore days. I wrote some fairly sophisticated assembly language code for a BBS package that I developed.. totally rewrote console I/O, etc. It was the only BBS software I ever saw where one could drop to "READY.", load, edit, and/or run other programs, and still handle the console and exceptional conditions such as carrier loss correctly... I remember being one of the VERY few people (half a dozen total, they said) who wrote a working bit of code to correctly answer a Volksmodem 1200 baud _dumb_ modem... one had to sit there and twiddle bits in exotic ways. Eccch. I think my real claim to fame was writing a bit of code that sat on the modem port listening for "CONNECT^M", "NO CARRIER^M", etc. as part of the data stream, because one never really knew if what one was seeing on the "control" lines of the modem port was reasonable and accurate... I spent many hours struggling with how the hell to get an AT command set modem to do precisely what I wanted, under all circumstances. :-( I do not consider modems with in band status and control capabilities to be fun. :-( :-( :-( :-( :-( :-( :-( :-( :-( :-( :-( :-( :-( > > > I tried using the patches, but they have one small problem. My modems > > > stupidly send a connect message in a way that getty sees as a username. > > > So it sits at Password: waiting for test, but only getting LCP. The other > > > times I got it to work(with different modems), it worked like a charm. > > > > Turn off result codes. > > > > ATZ > > ATQ1&W > > > > Also set the modem to do a reset on DTR transition. Then if you need to > > dial out, you can use "ATQ0" in your dial string to force the modem to > > provide result codes for the dialer program. > > This is good, but if your modem supports something like the "Q2" > command in which results are supressed (quiet mode) only in answer > mode, this is even better. Then you don't have to issue the "ATQ0" If your modem supports Q2, it probably supports reset on DTR or reset on carrier loss. I won't argue that it is good advice, however... > in the dial string or init string to dial out, nor guarrantee that > the modem was fully reset on each transition (though doing a reset > on the DTR transition is usually a win, anyway). I don't know how > many modems support this, but US Robotics Couriers and Sportsters > do, and they are quite popular. If your modem doesn't support Q2 > or something similar, then Joe's suggestion is the way to go. Junk alert: USR Sportsters. (Fine for casual home use, probably, but crummy if you are an ISP) > > No modem I have ever seen works out of the box correctly with a UNIX host > > for both in- and outdial applications. > > Strongly concur! :-) I have a small database of my "preferred defaults" for a number of varieties of modems.... usually these defaults include things such as shutting off the speaker and setting other parameters to allow for hardware flow control, ATS0=1, disable "+++", etc. I do not guarantee that all of them conform to this 100%, as some of them were done for particular reasons. AT&T Paradyne DataPort 14.4K (my favorite modem of all time) AT&F ATE0L3M0Q1S0=1S2=255S10=220 ATX1&C1&R0\D1\G0 AT&W0 Motorola Power 28.8 (probably identical for Premier/Lifestyle) AT&F ATE0M0Q2S0=1S2=255S10=220 AT&D3&R&S2\K5 AT&W USR Sportster V.34 AT&F1 ATE0L3M0Q2S0=1S2=255S10=220 ATS13.0=1 AT&W USR Courier V.34 AT&F1 ATE0L3M0Q2S0=1S2=255S10=220 ATS13.0=1S32=8S34.4=1 AT&W Telebit Trailblazer Plus (probably not quite conformant) AT&FS50=0S51=5S52=2S54=3S55=3S58=2 ATS66=1S68=255S95=2X1Q0E1 ATM0S0=1S2=255S10=220S64=1S92=1 AT&W Zoom 28.8 V.FC (don't ask why I have two of these - they are junk) AT&F ATE0M0Q0S0=1S2=255S10=220 AT&C1&D2%E2 AT&W0 I would only personally buy the Paradyne 14.4's, the Motorola 28.8's, or the Couriers. ... JG
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