3Com EtherLink 3C529 User Manual page 40

Changing the 3C529 Adapter Options 3-7
If you experience problems with your modem, such as
dropped characters or excessive retries, selecting a higher
option setting should help. If the problem is not due to
the EtherLink III driver, changing the option setting will
not make a difference.
NOTE: The default value (9600 baud) works whether
you have a modem or not, or even if the modem is slower
than the default (example, 2400 baud). Do not change
the default option setting unless you experience
problems.
If you experience compatibility problems between your
adapter and another device in the system other than a
modem, selecting a higher option setting may help.