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From: pdj@nbires.UUCP (Paul D. Jensen)
Newsgroups: net.micro
Subject: Re: modem noise problems.
Message-ID: <364@nbires.UUCP>
Date: Mon, 21-Jan-85 22:53:16 EST
Article-I.D.: nbires.364
Posted: Mon Jan 21 22:53:16 1985
Date-Received: Thu, 24-Jan-85 06:45:06 EST
References: <7574@brl-tgr.ARPA>
Organization: NBI,Inc, Boulder CO
Lines: 17

I think some of the problems with spurious { characters on 1200 baud
modems are unrelated to phone lines.  I have had considerable problems 
with my older Cermetek modem which they have been unable to correct.  

If I put the modem in analog looparound, and leave my terminal on all night, 
I receive a small number (1-10) of the spurious phase decoding errors 
(usually Del {).  Since there is no phone line involved, the error rate 
appears much too large for this type of logic, and about as bad 
as many phone lines (about 1 in 10**7).  The three replacements I had
varied by a factor of 10 in the error rates, but all showed errors.

Thus is appears that problems may exist in the clock recovery for
the phase decoding.
-- 
Paul Jensen
NBI
(303) 444-5710 x3054