USRobotics V.34 - Manual (Page 187)

COURIER HIGH SPEED MODEMS
Additional Operations G-5
Voice/Data Switch

S32=1, S32=2
1. Phone the other user to establish the bit rate, parity, word
length and number of Stop bits the other person's modem
accepts. (Both modems should be offline, in Command
mode.)
You and the other user must also agree on which modem
will go off hook in Originate mode and which in Answer
mode. The Courier is factory set to go off hook in Originate
mode, S32=1. The Answer modem should have S32 set to 2.
NOTE: If the stored command string command has been
used (&ZC=
s), the modem will default to S32=9, which
executes the stored command string when the voice/data
switch is pushed.
Either party's device can be the originate or answer modem;
it doesn't matter who made the phone call. But one modem
must first enter Originate mode and the other then enter
Answer mode.
2. Without hanging up the phone, press the voice/data switch.
If S32 is set to 2, Answer mode, press the voice/data switch
immediately
after the remote user forces the remote modem
off hook in Originate mode.
3. The other party should force the remote modem off hook in
Answer mode by pressing the switch.
If yours is the Answer modem (S32=2), the other party
should press the voice/data switch immediately
before you
do so.
4. If the remote modem has handset exclusion, the remote user
should also keep the phone off hook in order to switch back
to voice later. If the remote modem doesn't have handset
exclusion, you can try to switch back to voice later. Or, you
both can hang up your phones as soon as the modems go off
hook.