Paul, at 23:10 on Jan 23 1996, you wrote to Paul Markham...

PM> So far I've connected at 26,400 and 24,000. 

May not be relevant.  Here is a perfect example of the USRs speed-shifting
upwards after the initial connect (today):

23 Jan 06:58:13.75 Processing node 3:711/934 -- Ten Minute Limit
23 Jan 06:58:13.75 Dialing 02-436-1785
23 Jan 06:58:36.56 CONNECT 26400/ARQ/V34/LAPM/V42BIS
23 Jan 06:58:37.72 Ten Minute Limit (3:711/934{at}fidonet)
[ ... ]
23 Jan 06:58:48.44 End of WaZOO Session
23 Jan 06:58:48.47 Session with 3:711/934 Time: 00:00:11 Cost: $0.00
23 Jan 06:58:54.25 USRobotics Sportster 28800 V.34 Fax Link Diagnostics...
23 Jan 06:58:54.78 Modulation               V.34
23 Jan 06:58:54.81 Carrier Freq (Hz)        1829/1829
23 Jan 06:58:54.81 Symbol Rate              3200/3200
23 Jan 06:58:54.84 Trellis Code             64S-4D/64S-4D
23 Jan 06:58:54.88 Nonlinear Encoding       ON/ON
23 Jan 06:58:54.91 Precoding                ON/OFF
23 Jan 06:58:54.91 Shaping                  OFF/ON
23 Jan 06:58:54.94 Preemphasis (-dB)        8/4
23 Jan 06:58:54.97 Recv/Xmit Level (-dB)    29/12
23 Jan 06:58:54.97 Roundtrip Delay (msec)   18
23 Jan 06:58:55.19 Data Compression         V42BIS 2048/32
23 Jan 06:58:55.22 Equalization             Long
23 Jan 06:58:55.22 Fallback                 Enabled
23 Jan 06:58:55.25 Protocol                 LAPM
23 Jan 06:58:55.25 Speed                    28800/28800
23 Jan 06:58:55.28 Last Call                00:00:12
23 Jan 06:58:55.31 Disconnect Reason is     DISC Received
23 Jan 06:58:55.31 Exit after compressed mail with errorlevel 70
23 Jan 06:58:55.34 end, BinkleyTerm PE OS/2 3.04 alpha -watcom

As you can see, I connected at 26400, and although the entire call took
only 11 seconds, the modems had transparently retrained upwards to an
asymmetrical 28800 bps in both directions.  Interesting, wot?

Regards, Bill

--- Msgedsq/2 3.20