wtm@neoucom.UUCP (Bill Mayhew) (01/31/88)
Hi, I recently had the occasion to call an AT&T 3b1's on board modem from my Trailblazer. When the trailblazer placed the data call at 1200 baud into the 3b1 OBM, it thought that the 3b1 had MNP protocol, as reported by the Telebit's "CONNECT 1200/REL". At that point, the Trailblazer locked up, and I had to drop the DTR lead to get it to disconnect. The moral of the story is that you need to set "ATS95=0" before dialing into a 3b1 to disable the Trailblazer from trying MNP on the connection. The default setting should be "ATS95=2" so that the Trailblazer will use MNP if the other end has MNP and not use MNP if the other end is a vanilla modem. The only place this ever seems to have gotten me into troulbe is with the 3b1's OBM. So the question is, is the 3b1's OBM really supposed to be an MNP modem, and this 3b1 is sick? Or is the 3b1 an incomplete implementation of MNP, that never really was supposed to work? The 3b1's manuals don't say anything one way or the other about MNP. Bugs!... --Bill
dmk@dmk3b1.UUCP (David Keaton) (02/01/88)
In article <986@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: >. . . When the trailblazer placed the data call at >1200 baud into the 3b1 OBM, it thought that the 3b1 had MNP >protocol, as reported by the Telebit's "CONNECT 1200/REL". At that >point, the Trailblazer locked up, and I had to drop the DTR lead to >get it to disconnect. . . . >So the question is, is the 3b1's OBM really supposed to be an MNP >modem, and this 3b1 is sick? This is MNP's fault, not the 3b1's or the Trailblazer's. Before I got my Trailblazer, I experimented with mixing Multitech 224E's and other modems. Autoreliable mode is simply braindamaged. It disables Unix PC OBM's, USR Courier's, and other random modems. I finally gave up and I never use MNP any more. Behavior may vary slightly with Trailblazers, but the real problem is a design flaw in MNP. -- David Keaton dmk%dmk3b1@uunet.uu.net uunet!dmk3b1!dmk
jhc@mtunx.ATT.COM (Jonathan Clark) (02/02/88)
In article <986@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: >Is the 3b1's OBM really supposed to be an MNP modem? No. >The 3b1's manuals don't say anything one way or the other about MNP. Hardly surprising. -- Jonathan Clark jonathan.clark@mtune.att.com, attmail!jonathan Any affiliation is given for identification purposes only. The Englishman never enjoys himself except for some noble purpose.
stox@ttrde.UUCP (Kenneth P. Stox) (02/02/88)
In article <986@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: >. . . When the trailblazer placed the data call at >1200 baud into the 3b1 OBM, it thought that the 3b1 had MNP >protocol, as reported by the Telebit's "CONNECT 1200/REL". At that >point, the Trailblazer locked up, and I had to drop the DTR lead to >get it to disconnect. . . . >So the question is, is the 3b1's OBM really supposed to be an MNP >modem, and this 3b1 is sick? I have had the exact same experience using the MicroCom 9424C. The only solution was to disable the "Auto-Reliable" mode on the MicroCom. Apparently, something about the OBM on the 3B1 convinces the MNP modem that it is also a MNP modem. So, to answer your question, your OBM is fine, your 3B1 probably healthy. If someone out there in netland has a copy of the MNP specification, maybe you can let us in on why it behaves this way. -Ken Stox