HP 24SII - Manual (Page 69)

For example, suppose you want to communicate with a 2400 baud
modem connected to Port 2 of Module 2 and your PC is connected to
a computer port set at the Model 24SII's factory default serial
configuration (9600 baud, 8 data bit, 1 stop bit, no parity, and
XON/XOFF disabled). Port 2 of module 2 would need to be
configured to communicate at 2400 baud to match the baud rate of
the modem. However, you would configure your modem
communications package to communicate at 9600 baud to match the
baud rate of the computer port on the Model 24SII DES you are
connected to. You are now ready to make the connection to the
modem port through the Model 24SII DES.
NOTE: The Model 24SII DES does not pass hardware flow control
lines through the unit. If your modem package requires a change of
state in either the Data Carrier Detect or Ring Indicator signal lines, it
is suggested that you use the results codes option on both the
modem and your modem package when communicating through the
Model 24SII DES. Please refer to your technical documentation on
both your modem and your modem package on how to enable and
use the results codes.
NOTE: Your external modem should be programmed to have the
autobaud detect feature disabled. This is done by issuing the AT\J0
command for Hayes compatible modems.
Once you have finished your modem session, you must send the
disconnect sequence (i.e., the Port Select Code followed by
Enter/Return or Line Feed) to disconnect from the modem port and
allow other users access to the modem port.