Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!gatech!psuvax1!vu-vlsi!dsinc!syd
From: syd@dsinc.DSI.COM (Syd Weinstein)
Newsgroups: comp.dcom.modems
Subject: Re: V.32 @ 38,400 bps MNP Class 9 Microcom Modem? Is this for real???
Keywords: microcom, modem, MNP Class 9
Message-ID: <118@dsinc.DSI.COM>
Date: 27 Apr 89 01:02:28 GMT
References: <28111@cci632.UUCP>
Reply-To: syd@dsinc.UUCP (Syd Weinstein)
Organization: Datacomp Systems, Inc., Huntingdon Valley, PA 19006
Lines: 33

In article <28111@cci632.UUCP> sz@cci632.UUCP (Stephen Zehl) writes:
>-
>	I'm holding an advertisement from Microcom for their new V.32 modem
>that they claim runs at 38,400 bps in MNP Class 9.  A little asking around
>and I found that they list at $1395.00 and we can get them for as little as
>$800.00!!!!!  
>	Is this the END for TELEBIT TRAILBLAZERS!  We could save over
>$120.00 each buying these, and save a bundle on phone costs to boot.
This ones easy.  If you feed the mnp 9 v.32 modem uncompressed
restricted ascii source which it can compress to the limit, it
can indeed approach 38.4bps throughput using a long block protocol.
Note, uucp's protocol with its short packets doesn't lead to packing
the data stream quite so well.

However, and the big however, is that we currently send compressed
batched over the tb+'s for news.  Now the underlying rate of a v.32
is 9600 cps.  The underlying rate of a tb+ is at best 14000-18000 cps,
again faster than the v.32.

The tb+'s sending uncompressed ascii can easily do 19200cps and could
do even faster if telebit would make a rom change and allow 38400 to
and from the modem.  (Current top interface rate is 19200)

Thus for uucp, and compressed news transmission, the tb+ is still
a higher throughput modem.  About 1.3 to 1.4 times faster.

For restricted character set ascii, the mnp9 v.32 will be faster,
but how much data do you send that way and how much is compressed?
-- 
=====================================================================
Sydney S. Weinstein, CDP, CCP                   Elm Coordinator
Datacomp Systems, Inc.				Voice: (215) 947-9900
syd@DSI.COM or {bpa,vu-vlsi}!dsinc!syd	        FAX:   (215) 938-0235