Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!decwrl!fernwood!portal!cup.portal.com!schuster
From: schuster@cup.portal.com (Michael Alan Schuster)
Newsgroups: comp.dcom.modems
Subject: Re: USR Courier V.32bis questions etc....
Message-ID: <41497@cup.portal.com>
Date: 21 Apr 91 12:09:41 GMT
References: <6465@husc6.harvard.edu>
Organization: The Portal System (TM)
Lines: 38

>There seems to be an implication that one CAN NOT use data compression
>with the new 14,400 bps link rate.  I haven't seen anything real to explain
>this.  Is it true?  If so why?  I HOPE that one can use V.42bis compression on
>top of the V.32bis 14,400 bps link rate....

Untrue. Of COURSE you can use data compression. I have a new USR and have
gotten throughputs over 3000 cps on uncompressed text files.


>If these modems can theoretically reach throughputs of 57,600 bps, what
>is the highest DTE rate that they support?  I should think 57,600 bps would be
>necessary.  I ask because I was told two different things.  The USR people sai
d
>that the highest DTE rate was 38,400 bps.  The dealer I talked to told me that
>they went "much higher" than 38,400 bps.  What is the answer?

USR is correct; your dealer is wrong. Are you surprised?


>The dealer told me that USR ditched the Rockwell data pump for their own
>design and that the new modem should be much more reliable.  Does anyone have
>any thoughts or inside knowledge on how this might affect future upgrades?  I
>am imagining a fax upgrade, I guess, as a possibility....  I know that chips
>with fax capability are becoming more common, and that, among others, Rockwell
>has them....

In my opinion this was an excellent move. The DSP functions are now done by
two TMS 32025 chips. Their firmware is OFF BOARD ... on two 27512 eproms.
The third piece of firmware is another 27512 which runs the 80188-16
and runs the modem's general operations. These three chips can be swapped
out for $15 and can TOTALLY CHANGE THE PERSONALITY OF THE MODEM at will.
Thus, future upgrades are bound only by the capacilities of the chipset
and what USR is willing to write for them.


 Mike Schuster                                      |    CIS: 70346,1745
 NY Public Access UNIX:  ...cmcl2!panix!schuster    |    MCI Mail, GENIE:
 The Portal (R) System:  schuster@cup.portal.com    |           MSCHUSTER