AT&T 3.0 manual Pft, Pri

Glossary

PFT	(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.
pool	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.
port	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.
Power Failure	See PFT.
Transfer
power supply	Device that directs electricity to modules and telephones
module	on the system. One power supply module is needed for
	each carrier, and an auxiliary power unit is added if the
	module exceeds capacity.
PRI	(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-channelsfor voice and/or data and one
	64-kbps D-channel,which carries multiplexed signaling
	information for the other 23 channels.
primary system	First jack on the first MLX or analog multiline extension
operator position	module in the control unit, that is, the extension jack with
	the lowest logical ID in the system.
prime line	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.

GL–26Maintenance and Troubleshooting