THE SOLUTION: On the home modem, remove the modem init string "AT&Q0" to
allow the default AT&Q5 to take effect. &Q5 turns on V.42 error correction.
&Q0 turns it off and also turns off data buffering.
EXPLANATION: The old init string worked for years, but it was only recently
that we started using the 38400 baud modem on the Sun workstation operating
at its high speed. The old settings worked because data was never being
sent faster than the modem could handle it. I homed in on the solution
by dialing in to another system with the same modem at slower speed and
noticing that it worked fine, as was suggested by a few people.
To all those who diagnosed the problem as one of flow control, a virtual
handshake. While it was not a matter of hardware or software handshaking
incompatibility, it did lead me to examine every single aspect of the home
modem's settings and become a bit confused about why &Q0 was in the init
string.