AT&T MERLIN LEGEND Installation & Maintenance Manual page 212

Installation
a D6AP cord
Before installing the MFM, consider the following:
The KS22911,L2 power supply must be connected to an
electrical outlet that is within 50 feet of cord length of the MLX
telephone.
If you are connecting an MFM and two Direct Station
Selectors (DSSs) to the telephone, a 329A power unit is
required. (The 329A power unit must be ordered separately.)
A longer D8W telephone cord is required if the wall jack is
more than 7 feet from the MLX telephone.
Note: The MFM uses one of the two B channels when it is active.
This means that when an accessory, such as a fax machine, and
the MLX telephone are in use at the same time, Voice Announce
to Busy is not possible. (Voice Announce to Busy is a feature that
allows users to be paged on the speakerphone even if they are
on a call.)
Procedure
WARNING:
Before installing the MFM, disconnect all cords (line and/or
power) attached to the MLX telephone. This is to ensure that
no hazardous voltages are present during assembly.
Ringing voltage from the MFM attached to the MLX
telephone can cause electrical shock if adjustments are
made while the cords (line and/or power) are connected.
Follow these steps to install and replace an MFM and change its
pin settings.
1. Remove the user card tray from the bottom of the desk stand
on the telephone.
3-104 Telephones and Consoles