Path: utzoo!attcan!uunet!mailrus!accuvax.nwu.edu!nucsrl!telecom-request
From: thomas%mvac23.uucp@udel.edu (Thomas Lapp)
Newsgroups: comp.dcom.telecom
Subject: Re: Data Access Lines
Message-ID: <8537@accuvax.nwu.edu>
Date: 1 Jun 90 01:56:18 GMT
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X-Telecom-Digest: Volume 10, Issue 406, Message 1 of 8


David Tamkin wrote:

> If PEP is modulated only at 7.35 or 88.26 baud, it should be no
> difficulty for the local lines to carry it, unless shoving so many
> bits into so few bauds requires so many carrier pitches that local
> telco lines might not be reliably able to discriminate that fine.

Aren't we forgetting the fact that some of those 511 channels that the
Telebit uses are outside the frequency range that the telco promises?
I think the telco says that you'll have decent output at something like
300 Hz to 3000 Hz (or is it 2700Hz?).  I thought I read that the
Telebit tries to use more of the frequency spectrum (like maybe up to
4000 Hz?).  So if the channels outside the promised range are unusable,
the telco isn't doing anything wrong, and the modem may not (at 88.26
baud) be able to use enough channels in-band to send at the higher bit
rates.

Just a thought.

 - tom

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