Re: (PM) Serious phone connection issue...

Dick St.Peters (stpeters@NetHeaven.com)
Wed, 12 May 1999 10:22:54 -0400

Jeff Haas writes:
> Another possibility: The lines have been rolled to a lite-span or
> equivalent technology running in Universal mode. Same problem.
>
> (Does anyone have a good explanation of why a LS in Universal mode
> has this problem? To the best of my understanding, you are still
> getting a 56K channel, but it is supplying another A/D conversion.
> The necessity of this extra conversion is the bit I don't understand.)

I'll take a stab. Taking what I know and extending it a bit with some
extrapolation and seasoning with conjecture:

Universal mode is the classic DLC/SLC way of running lots of lines to
a remote site. You take analog out of the switch, redigitize it,
carry the new digital signal to a remote unit, and convert back to
analog. It's called "Universal" because it will work with any switch;
they all output analog.

The other attachment mode at the switch is "Integrated". This takes
digital out of the switch, bypassing the switch's D/A and avoiding the
need for redigitizing analog. It's called "Integrated" because it
requires special cards in the switch, making the LightSpan (or
whatever brand) an extension of the switch rather than just a carrier
of lines.

Imagine a third-party T1 card for a PM3, and you'll get a hint of why
telcos and switch mfrs do not like Integrated attachment.

--
Dick St.Peters, stpeters@NetHeaven.com 
Gatekeeper, NetHeaven, Saratoga Springs, NY, 1-800-910-6671 (voice)
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