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From: dold@mitisft.Convergent.COM (Clarence Dold)
Newsgroups: comp.dcom.modems
Subject: Re: High speed modems and voice lines
Message-ID: <1527@mitisft.Convergent.COM>
Date: 7 Jul 90 06:42:57 GMT
References: <37442@ucbvax.BERKELEY.EDU>
Distribution: usa
Organization: Convergent Technologies, San Jose, CA
Lines: 20

in article <37442@ucbvax.BERKELEY.EDU>, hegarty@janus.Berkeley.EDU (Christopher Hegarty) says:
> 
> I have a Telebit T2500 on my workstation at Berkeley and another T2500
> at my home six miles away.  Both modems are connected to voice-quality
> lines via standard jacks.  I've been having problems with this setup
> and wonder if anyone can help.
You might actually have too strong a signal.  Check for a dBm level jumper
in the modem.  Some can drive the line at either -12dBm or -9dBm.
Central office equipment is intended to receive -13dBm.  If you only have 
1 db of loss on your line, the normal -9 setting is too hot, and causing 
distortion.  You can actually measure the loss by dialing in to a special
number in your prefix, and measuring RMS volts with a digital meter.  I've
got the desired readings in a file somewhere, but the name escapes me.
All Telco is going to do with their 'adjustments' is to trim your modem
output to the proper level.
-- 
---
Clarence A Dold - dold@tsmiti.Convergent.COM            (408) 435-5293
               ...pyramid!ctnews!tsmiti!dold        FAX (408) 435-3105
               P.O.Box 6685, San Jose, CA 95150-6685         MS#10-007