Path: utzoo!utgpu!watserv1!watmath!att!dptg!ulysses!andante!mit-eddie!wuarchive!cs.utexas.edu!evax!utacfd!letni!mic!ernest!shibaya!afc
From: afc@shibaya.lonestar.org (Augustine Cano)
Newsgroups: comp.dcom.modems
Subject: Re: Telebit T2500 problem with internal 2400 modem
Keywords: T2500, internal 2400 do not work together
Message-ID: <1990Sep8.215628.1369@shibaya.lonestar.org>
Date: 8 Sep 90 21:56:28 GMT
References: <9197@uhccux.uhcc.Hawaii.Edu> <9209@uhccux.uhcc.Hawaii.Edu>
Reply-To: afc@shibaya.lonestar.org (Augustine Cano)
Distribution: na
Organization: Multidisciplinary Designs Unlimited
Lines: 37

In article <9209@uhccux.uhcc.Hawaii.Edu> todd@uhccux.UUCP (Todd Ogasawara) writes:
>In article <9197@uhccux.uhcc.Hawaii.Edu> todd@uhccux.uhcc.Hawaii.Edu (Todd Ogasawara) writes:
>>Has anyone else had problems dialing into a Telebit T2500 with PC internal
>>2400 baud modems? Here's my problem. I can dial into my Interactive UNIX
>>2.2 system equipped with two T2500 modems with a variety of other high and
>>low speed modems (T2500, T1000, Hayes 1200, Worldport 1200, Everex Evercom
>>24, and Everex 24+) with and without MNP 5. However, if I try to dial into
>>the T2500 with an internal 2400 bps modem (in this case and Everex Internal
>>24+ or a Toshiba T5100 2400bps internal modem), I cannot get a connection.
>>The T2500 just cycles through the various protocols and I never get a sync.
>>I've tried a variety of workarounds: adding ",,,," to the end of the phone
>>number (e.g., ATDT 123-4567,,,,), turning off MNP, etc.
>
>To followup on my own question... I called Telebit tech support this
>morning. A tech support staff person called back a few minutes ago and we
>spent some time verifying that the Toshiba laptop internal 2400 modem does
>indeed fail to connect with a T2500 at 2400 baud. The only way we could get
>a connect was to force the T2500 to stay at 2400bps (S50=3, S51=2). If the
>T2500 is set to autobaud, no connect. Again, this seems to be unique to the
>internal 2400 modems from Toshiba and Everex. External 2400 and 1200bps
>modems seem to work fine with the T2500.
>
>Telebit is looking into this...todd

Good! I hope they fix whatever it is.  It has been known for a while (and
I just experienced it) that telebits (trailblazers for sure, I don't know
about the others) will not talk to the OBM (on board modem) in the AT&T
Unix pc (3b1 & 7300) if the interface speed is locked.  If you let the
interface speed follow the modem speed, there is no problem.

>-- 
>Todd Ogasawara, U. of Hawaii
>UUCP:		{uunet,ucbvax,dcdwest}!ucsd!nosc!uhccux!todd
>ARPA:		uhccux!todd@nosc.MIL		BITNET: todd@uhccux
>INTERNET:	todd@uhccux.UHCC.HAWAII.EDU

Augustine Cano		afc@shibaya.lonestar.org