flexfax: communication failure during phase C

[Dave Lewis <dlewis@appn.ci.in.ameritech.com>]

Hello all.
I'm getting occasional above errors with an AT&T DataPort 14.4 modem I 
just installed a few days ago.  The error always occurs at the end of 
sending a page of data, and it is a timeout;  it's as if the receiving 
modem does not recognize whatever commands are used to signify the end of 
a page.  The problem appears to be random, and happens maybe 1 in 10 
fax-send sessions.  Here's the end of a typical failed-session log file:
Oct 21 10:41:47.09: [66246]: <-- data [1027]
Oct 21 10:41:47.95: [66246]: <-- data [1026]
Oct 21 10:41:48.96: [66246]: <-- data [1028]
Oct 21 10:41:49.24: [66246]: <-- data [1026]
Oct 21 10:41:49.51: [66246]: <-- data [1024]
Oct 21 10:41:49.78: [66246]: <-- data [1026]
Oct 21 10:41:50.04: [66246]: <-- data [1024]
Oct 21 10:41:50.31: [66246]: <-- data [15]
Oct 21 10:41:50.58: [66246]: SENT 25615 bytes of data
Oct 21 10:41:50.58: [66246]: <-- data [2]
Oct 21 10:41:51.38: [66246]: SEND end page
Oct 21 10:44:51.38: [66246]: MODEM <Timeout>
Oct 21 10:44:51.38: [66246]: <-- [6:AT+FK\r]
Oct 21 10:44:51.53: [66246]: --> [5:AT+FK]
Oct 21 10:44:51.53: [66246]: --> [5:ERROR]
Oct 21 10:44:51.53: [66246]: MODEM Command error
Oct 21 10:44:51.53: [66246]: <-- [5:ATH0\r]
Oct 21 10:44:51.67: [66246]: --> [4:ATH0]
Oct 21 10:44:51.67: [66246]: --> [2:OK]
Oct 21 10:44:51.67: [66246]: SESSION END

You can see the timeout from 10:41-10:44.  Any ideas?  This is a class2 
modem.  Thanks, Dave Lewis