Thanks again for your help Hauke,

>> 57600   modem cdtrcts  at&fe0     modem hung up on 3 attempts when ftp
>> started
>
> That's why you need "AT&D0".

> The throughput you will get is limited by tty speed. Try 57k6 with hardware
> handshake

I added AT&D0 and got these results:

serial   control        init      kB/s
 38400   <none>         at&f      2.40
 38400   cdtrcts        at&f&d0   2.56
 57600   <none>         at&f&d0   3.34
 57600   cdtrcts        at&f&d0   3.19, 3.33, 3.89, 3.27   (repeated tests)
 57600   cdtrcts        at&f&d0  11.10, 4.02, 4.88
115200   cdtrcts        at&f&d0   3.14

> and you will see a performance like in MacOS.

I'm getting close, I think. The 11kB/s sustained transfer above indicates that my set up is capable, though I've yet to see the same consistency as my Mac OS router.

Thanks for all your help. Any other suggestions are welcome.

Tom
T&B