VA4224 won't talk to 3B1

jhc at mtune.UUCP jhc at mtune.UUCP
Sat Mar 7 14:49:08 AEST 1987


In article <1950 at cit-vax.Caltech.Edu> mangler at 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.



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