AT&T MERLIN MAIL System Programming And Maintenance Manual page 45

Installation
The ring generator should be installed in the power supply module of the
carrier, either basic or expansion, containing the 012 module to which the
MERLIN MAIL—ML system ports are connected.
NOTE:
:
For 012 module model 517G13, the ring generator is built-in. A separate
ring generator is not needed in the power supply module.
The following chart lists the number of devices that can be supported at the
same time by a 012 module, model 517F13 or earlier, when MERLIN
MAIL—ML is installed:
MERLIN MAIL—ML
Configuration
2 port
4 port
The 012 module, model 517G13, can have its 12 ports used as MERLIN
MAIL—ML ports, faxes, or single line sets, if a sufficient number of touch-tone
receivers are available in the system. The limiting factor is the touch-tone
receiver needs of all devices connected to the 012 module as well as the
number of devices that can be supported to ring simultaneously.
R M D
Fax
1
1
Single Line Sets
1
1
Preparing for Installation
3
2
2-3