🚀 go-pugleaf

In article <385b8df7.4704295@news.netdirect.net.uk>, Barry Schofield
<bscho@lioncom.net> writes
>On Wed, 08 Dec 1999 08:51:01 +0000, Paul Black <paul.black@oxsemi.com>
>wrote:
>> - What about compression? Demon provide STAC and MS-STAC but the web page
>>   mentions "V.42bis Data Compression over ISDN using V.120 & X.75", are
>>   they different terms for a similar thing or does it mean STAC/MS-STAC is
>>   not supported?

As Faye has already answered, V.42bis is rarely used on ISDN. For
Internet connections you normally used sync PPP and do your compression
at the PPP level using some flavour of STAC.

If you're using a Microsoft OS with Demon, you can use the MS stack to
handle the compression for you - set your Demon setting to MS_STAC, turn
"Enable software compression" on and use the Green ROMP (or the Red/Blue
ROMP if you're using Windows 9x).



>V.42 bis is the analogue world just as V.120 & X.75 are interim
>bridges between the analogue world and ISDN. None of these are
>necessary now and were only used in the early days of ISDN.

V.120 and X.75 are very necessary for making ISDN calls to other ISDN
devices where you don't want to talk PPP. Kindly engage your brain
before writing, Barry. V.110 is highly useful too - for making digital
data calls on GSM.


>PPP sync is the most common connection protocol -the internet
>standard- and now STAC is the digital compression de-facto standard.

Considering that there are several flavours of STAC around, and none of
them are quite standardised, there are interworking issues between
different manufacturer's kit and various patents flying around, too, the
latter statement is a gross oversimplification. There again, it's a
Barry post - what do you expect?





David
-- 
David Wood
david@wood2.org.uk      ** NOTE NEW ADDRESS **
My old address, david@wood2.demon.co.uk, will continue to work for an
indefinite period, but please update your address book if relevant.