AT&T MERLIN LEGEND Release 2.0 Programming Summary Manual page 173

Auxiliary Equipment
Fax
Use this procedure to identify the station jacks used to connect fax machines.
In addition, specify the telephones to receive a message-waiting indication
(MWI) when a fax transmission is received, and specify the length of time
before the system registers that a fax has arrived and sends the message-
waiting indication.
NOTE:
Do not use this procedure for fax machines connected to analog multiline
telephones via a General Purpose Adapter (GPA) because features
cannot be assigned to the fax independently of the telephone in a GPA
configuration.
A maximum of 16 fax machines can have the Fax Message Waiting feature.
[Additional fax machines (more than 16) can be installed, but these machines
cannot have this feature.]
You can specify up to four telephones to receive the message-waiting
indication when a fax transmission is received. Note that fax machines can
only send and not receive message-waiting indications.
10-5
Fax