G'day Bill,
 
 BG> Possibly because you did not disable MNP5, although the difference
 BG> should not have been that great.  The simple fact is that MNP's 256
 BG> byte frames suffer from less protocol overhead than LAPM's 128 byte
 BG> data frames, and the overall cps rates under MNP4 are measurably faster
 BG> as a result.  
 AM> It also states in the Netcomm Automodem reference manual 
 AM> that V.42 and V.42bis give better performance than MNP by up 
 AM> to 50%. It showed a table.

Yep, tried MNP, disabled all compression and got 3320 cps, with 256 byte
blocks which is about a 40cps improvement, but I had no compression.
I'm going to stick with V.42 and V.42bis for the moment.

 BG> That relates to the difference between BTLZ (4:1) and MNP5 (2:1) data
 BG> compression, and has nothing to do with MNP4 or LAPM.
 
 AM> Well, I'm not sure. If you know how to choose MNP4 over 
 AM> MNP2, I'll give it a shot.

 BG> Not sure on Rockwell clones, as the command varies between
 BG> manufacturers.  Try &Q3 (but check your manual to make sure first).
 
I've got a Roadster, I'll take a look.

What CPS rates do you get on your Courier at 28.8K with V.42 and V.42bis?
(ZIP file and Zmodem)

cya
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