Date: Sun, 22 Dec 1996 16:10:13 -0700 (MST) From: Don Yuniskis <dgy@rtd.com> To: drussell@internode.net (Doug Russell) Cc: freebsd-questions@freebsd.org Subject: Re: your mail Message-ID: <199612222310.QAA08932@seagull.rtd.com> In-Reply-To: <1.5.4.32.19961222212543.007051e4@internode.net> from "Doug Russell" at Dec 22, 96 02:25:43 pm
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> >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. > > You aren't ENTIRELY correct. If set up properly, the +++ sequence SHOULD > work properly. a +++ in the datastream won't trigger going into command > mode unless there has been no data sent for a specified delay period. (See > S12 in your modem's S-Rigister table. From a Courier HST V/Everthing: Sets > the duration, in fiftieths of a second, of the guard time for the escape > code (+++) sequence.) Default is 50 (1 second)). So, in other words, you > have to not just have a +++ come over the connection, but at least a one > second pause, a +++ (and only a +++) then another 1 second or longer pause, > in order for the modem to go into command mode. It is possible, but highly > unlikely. Easier to just disable the +++ sequence -- change your "escape character". I don't like things that are "highly unlikely" -- that tends to mean their probability of occuring is damn close to 100%! :-( > Of course, this is not the "proper" way of hanging up a modem. The > generally accepted method (especially with UNIX systems) is to drop DTR. > The modem should be set to at least hang up, if not do a full reset, on DTR > drop. > > I have always set my modems this way under DOS, and under UNIX. > > Biggest reason with a good old term program in DOS? It takes MUCH less time > to do a vDTR^ than it does to wait a second, +++, wait a second, ATH. Yes. ALso there are other things besides PC's (etc.) in the world that actually *use* these signaling conventions! --don
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