Path: utzoo!attcan!uunet!cbmvax!grr
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.dcom.modems
Subject: Re: Can we back up a sec?
Message-ID: <15441@cbmvax.commodore.com>
Date: 28 Oct 90 23:52:24 GMT
References: <1288.27204357@zswamp.fidonet.org> <1990Oct25.033248.28581@m2xenix.psg.com>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 30

In article <1990Oct25.033248.28581@m2xenix.psg.com> news@m2xenix.psg.com (Randy Bush) writes:
> root@zswamp.fidonet.org (Geoffrey Welsh) writes:
> 
> > The question at hand is whether the full-duplex nature of V.32 extends this
> > situation to 9600 bps.
> 
> I use V.32 and PEP for many connects a day.  I normally use a T2500, but have
> also used Intel's new 9600EX (damn nice modem, and damn inexpensive, BTW).  A
> local V.32 connect is as fast as PEP.  A long distance V.32 connect is
> significantly slower.  I.e., local V.32 gets over 1,000 cps, while a looong
> distance one (i.e., Oregon to Africa) gets 550 cps.

I find this quite confusing and contrary to my own experience.  Local PEP calls
are almost always faster than V.32, while long distance/international PEP calls
do sometimes dip below the rates expected for 9600 BPS (i.e. V.32) connection.

The only way that V.32 can "slow down" is via repeated retraining, or posibly
fallback to 4800 BPS.

The following seem to be the three killers of telebit thruput (though I'd rather
lose thruput than take a bit hit on call completion/reliability).

1) International Calls - Europe, Hong Kong, etc...
2) Systems with T1000's or Trailblazers locked at 9600 BPS.
3) Highly loaded systems that can't keep up with the modems.

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)