Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!burl!codas!mtune!jhc
From: jhc@mtune.UUCP
Newsgroups: comp.dcom.modems,comp.sys.att
Subject: Re: VA4224 won't talk to 3B1
Message-ID: <1022@mtune.ATT.COM>
Date: Fri, 6-Mar-87 23:49:08 EST
Article-I.D.: mtune.1022
Posted: Fri Mar  6 23:49:08 1987
Date-Received: Sun, 8-Mar-87 15:46:54 EST
References: <1950@cit-vax.Caltech.Edu>
Reply-To: jhc@mtune.UUCP (Jonathan Clark)
Organization: AT&T ISL Middletown NJ USA
Lines: 21
Keywords: Vadic, AT&T PC7300
Xref: utgpu comp.dcom.modems:331 comp.sys.att:226

In article <1950@cit-vax.Caltech.Edu> mangler@cit-vax.Caltech.Edu (System Mangler) writes:
>Our Vadic VA4224 rack-mount dialout, which works fine with over 25
>UUCP sites, refuses to originate a connection to an AT&T PC7300.

Early versions of the modem chip used in the UNIX PC, among other
products, were very strict about the amount of deviation allowed from
the fundamental comms frequency, which is published in some standard
or other. I understand that the allowed amount was bang-on the
standard. Certain other modems do not meet this standard. The problem
is exacerbated by the fact that the 212 (the standard!) will function
perfectly happily with massive amounts of slop in the speed. Newer
chips allow rather more deviation.

In addition, this modem chip is really fanatical about getting a full
stop bit - shaving of these will result in totally unreliable
transfers (they alarm out and die).
-- 
Jonathan Clark
[NAC,attmail]!mtune!jhc

My walk has become rather more silly lately.