3Com ISDN Modem manual Isdn Service from Pacific Bell, Switch back to the first call?

	Supplementary Voice Features	6-5
Table 6-3 How to Use Call Transfer
How Do I	Do This
Cancel the second call and	If the dialed party is busy, press and release the switch
switch back to the first call?	hook button to cancel the attempted call and
	reconnect you to the first call. If you should hang up,
	the phone will ring back, indicating that you have a
	call on hold.

If you dialed a wrong number, or the far end does not answer, hang up the phone to abort the attempted call. The phone will then ring, indicating that the first call is on hold. Answer the phone to reconnect you to the first call.

If you experience difficulty implementing any of the Supplementary Voice Features, confirm that you have these features enabled on your ISDN line, and that the default Call Conferencing, Call Transfer, and Call Drop S register values (S77, S78, and S79) match the values required by your telephone company.

ISDN Service from Pacific Bell

If your ISDN line has been provisioned through Pacific Bell, and you are having difficulty implementing Call Hold, Call Drop, Call Conference and Call Transfer, you may need to make three additional S register changes to take advantage of these Flexible Calling features.

1Contact Pacific Bell and discern the appropriate Call Hold, Call Drop, Call Conference and Call Transfer key values.

2Launch your terminal emulation software.

You will need to change the values of S registers 77, 78, and 79.

3Send the following command to the 3C882 ISDN modem:

AT S77=x S78=x 79=x

(where x is the key value supplied by Pacific Bell) and press [Enter] or [Return].