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Date: Thu, 23 Jan 1997 13:04:54 -0600
To: Brett_Glass@infoworld.com, John-Mark Gurney <gurney_j@resnet.uoregon.edu>,
        lenc@earth.infinetconsulting.com
From: Allen Hyer <allenh@wtrt.net>
Subject: Re: 56K vs X2?
Cc: spork@super-g.com, batie@agora.rdrop.com, drussell@internode.net,
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At 09:40 AM 1/23/97 PST, Brett_Glass@infoworld.com wrote:
>> basicly there isn't signal loss when you go from digital to analog...
>> there is only loss when you go from analog to digital...
>
>Not true; there's distortion, introduced by encoding, in either direction.
>Not to mention bit robbing.

That would normally be true.  I can only speak from what I have read about
X2, really haven't studied Lucent's 56k.  T1's use PCM codes to carry data.
 USR's digital X2 modems signal the direct PCM codes, so there is no
conversion in the server side originated data until it hits the local loop
on the customer's phone line.  And, since the originating data was straight
PCM codes, the digital to analog conversion should theoretically not change
the data.

Allen Hyer
System Administrator
West Texas Rural Telephone