Panasonic KX-TD7685 Operating Instructions Manual page 31

To set/cancel for intercom calls
To set/cancel for outside calls
To talk to the new party (While hearing the Call Waiting tone)
To terminate a current status
To hold and then talk to the new party
OR
Disregard this step if both parties are extensions.
To page
Paging Group No. (2 digits)
Wait for an answer.
To answer
Document Version 2008-01
Call Waiting
No call
Tone
No tone
Tone
(rapidly flashing F-CO Key [0-9, , #])
OR
(rapidly flashing F-CO Key)
Paging
Operation
(Announce)
31