Date: Sat, 21 Dec 1996 10:51:29 -0700 (MST) From: Nate Williams <nate@mt.sri.com> To: dicen@hooked.net Cc: Chuck Robey <chuckr@glue.umd.edu>, freebsd-questions@freebsd.org, freebsd-current@freebsd.org, freebsd-stable@freebsd.org Subject: Re: User ppp not hanging up modem. Message-ID: <199612211751.KAA27123@rocky.mt.sri.com> In-Reply-To: <32BBA85F.41C67EA6@hooked.net> References: <Pine.OSF.3.95.961221100409.6960B-100000@professor.eng.umd.edu> <32BBA85F.41C67EA6@hooked.net>
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> Okay I have an update on the modem. My modem is a SupraFaxModem 14.4k > V.32bis externel sold for Macs. I got it not because I used to have a > mac but because I needed that type of cable it came with. This modem is > set by default not to do anything on a DTR transition. To hang it up you > do the correct thing which is escape with "+++" and then execute ATH. > User ppp only seams to cut the DTR. That's *NOT* the correct thing. What happens when for some reason PPP happens to send the sequence '+++' to the modem? All of a sudden it'll drop into command mode and you're screwed. User-PPP (as well as all other PPP/SLIP implementations I've worked with) assumes that you've disabled the escape sequence at least temporarily. > So I have now set the modem to be a PC type which will go into command > state with a DTR transition. This introduces other problems. Since > cutting DTR now doesn't reset the state of the modem, it just hangs it > up, doing a redial right after will not work. You have to wait a couple > seconds. Umm, what's wrong with 'waiting' a couple of seconds? If the line goes down you should wait for the other end to clean up in any case, simply because you never know what caused the line to go down, and waiting 5-20 seconds might clear it up and allow you connect up the next time w/out having to retry. > I can issue special commands to the modem to fix this but these > commands are not standard. Actually my modem practicaly has an OS in > it, it is so complex. Umm, *every* modem that has been sold in the last couple years has the ability to reset itself when DTR goes low. That includes a *really* old Telebit modem from the late 80's or early 90's. > This really needs to be put in the FAQ. I would rather have an escape > done "+++" and the an ATH to hang up the modem but atleast it works now. > Is this code in the termios library? I haven't look in my books yet. This code isn't in any 'unix-like' system program that I'm aware of. The standard practice on unix machines 'since time began' has been to reset when DTR goes low. Most of this *is* already documented in the FreeBSD handbook. Nate
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