Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!FHCRCVAX.BITNET!JOE
From: JOE@FHCRCVAX.BITNET (Joe Meadows)
Newsgroups: comp.os.vms
Subject: RE: Re: DECSERVER 200's and dial in/out modems
Message-ID: <UWAVM.ACS.WASHINGTON.EDU:LDiGoxv4*>
Date: 20 Jan 88 05:25:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 26


        I'd like to respond to an earlier discussion about multiple speed
incoming/outgoing modem use on a DEC Server 200.

        The manual does clearly state thet it can support TWO speeds, a
primary speed and a secondary speed. I assumed this was true for incoming
calls only, however, I was wrong. I have a Hayes 2400 baud modem set up
with a primary speed of 2400, and secondary speed of 1200. Incoming calls
switch correctly (note that you need pin 12 (or 23 I think, but 12 is the
more correct one) wired up for the modem to be able to tell the server
wether it is running in high or low speed. Much to my surprise my outgoing
calls also were switching to 1200 when I called slow machines. Actually,
to be honest, I haven't called out to a machine that has a 2400 baud modem,
so I could actually have screwed something up, but I doubt it very much,
since (a) my primary speed is 2400, hence I do an AT command at 2400 baud
(from server to modem), the modem switches to 1200 baud (and lowers the
signal on pin 12, indicating low speed) and so the server (noticing the
pin 12 state change) starts sending and receiving at 1200.

        Since only one pin designates low or high speed, the modem
can only switch between two speeds. To support more than two speeds
you would need a smarter modem, someone suggested a paradigm, I believe
a Telebit trailblazer would also do the trick.

        Cheers,
        Joe Meadows     Joe@fhcrcvax.bitnet