On my regular call to Denver, Colorado, USA I used to get 16800 bps
connects most of the time, with about 10 percent of the calls connecting
but failing due to low S/N ratio, failure to negotiate error correcting
protocols and retraining.

Checking the logs for the past couple of months I've found that most calls
now connect at 24000 bps (up to 34 dB S/N ratio), with some calls at 16800
bps, and a few really bad calls (down to a 7200 bps / V.34 call with 9dB
reported S/N ratio). 

As successive calls can be bad then good, it doesn't appear to be a local
loop or modem problem, but that different carriers in the USA have a really
mixed bag of equipment that is unmonitored )-:.

It appears that overall the call quality has improved during the time I've
had the Motorola Codex 3266 Fast V.34 modem with 7.7 firmware, but that the
lack of accountability of some of the US carriers still leads to situations
of call quality unacceptable even for voice use.

--- msgedsq 2.1