Friday, October 27, 2006

PBX Functions

Functionally, the PBX performs three main duties:

Establishing connections (circuits) between the telephone sets of two users. (e.g. mapping a dialed number to a physical phone, ensuring the phone isn't already busy)
Maintaining such connections as long as the users require them. (i.e. channeling voice signals between the users)
Providing information for accounting purposes (e.g. metering calls)
In addition to these basic functions, PBXs offer many other calling features and capabilities, with different manufacturers providing different features in an effort to differentiate their products. Common capabilities include (manufacturers may have a different name for each capability):

Auto Attendant
Automatic call distributor
Automated directory services (where callers can be routed to a given employee by keying or speaking the letters of the employee's name)
Automatic ring back
Call accounting
Call forwarding on absence
Call forwarding on busy
Call park
Call pick-up
Call transfer
Call waiting
Camp-on
Conference call
Custom greetings
Customised Abbreviated dialing (Speed Dialing)
Direct Inward Dialing
Direct Inward System Access (DISA) (the ability to access internal features from an outside telephone line)
Do Not Disturb (DND)
Follow-me
Music on hold
Night service
Shared message boxes (where a department can have a shared voicemail box)
Voice mail
Voice paging (PA system)