AT&T MERLIN LEGEND Release 3.0 Installation Manual page 596

Glossary
PFT
pool
port
Power Failure
Transfer
power supply
module
PRI
primary system
operator position
prime line
GL–26 Maintenance and Troubleshooting
(Power Failure Transfer) Feature that provides continuity of
telephone service during a commercial power failure by
switching some of the system's trunk connections to
telephones connected to specially designated extension
jacks.
In Hybrid/PBX mode, a group of outside trunks that users
can access with a Pool button or by dialing an access
code on an SA button. Also used by the ARS feature when
choosing the least expensive route for a call.
See jack. Also, refers to extension or line jacks before
these are numbered according to the dial plan during
programming. The lowest jack on a module is always
Port 1.
See PFT.
Device that directs electricity to modules and telephones
on the system. One power supply module is needed for
each carrier, and an auxiliary power unit is added if the
module exceeds capacity.
(Primary Rate Interface) Standard interface that specifies
the protocol used between two or more communications
systems. As used in North America, provides twenty-three
64-kbps B-channels for voice and/or data and one
64-kbps D-channel, which carries multiplexed signaling
information for the other 23 channels.
First jack on the first MLX or analog multiline extension
module in the control unit, that is, the extension jack with
the lowest logical ID in the system.
Individual extension number assigned to a telephone in a
system operating in Behind Switch mode. Each telephone
user has his or her own prime line and is automatically
connected to that line when he or she lifts the handset.