Abbreviated dialling
Agent features
Alert calling
Attendant
Authority code
Auto answer
Auto hold
Auto line selection
Auto transfer
Call forwarding
Call parking
Call pickup
Call transfer
Callback
Camp- on
Class-Of-Service
Conferencing
DISA
Distinctive ring
Do Not Disturb
Drop timeout
Exchange lines
External loud bell
External paging
Feature check
Feature codes
Forced Account Code
Forced call diversion
Group listen
Headset mode
Hold
Hot keypad
Hotline
Least Cost Routing
Lock / Unlock
Look-up
Messages
Music-on-hold
Mute
Names
No-ring transfer
Numbering plan
Off-hook Voice-Announce
Paging
Power-fail telephones
Private-to
Re-dialling
Reminder service
Service modes
SMDR
Tenant groups
Toll Restriction
U.C.D.
Virtual numbers

This feature allows a user to choose which system resource they access when they go off-hook; intercom dialtone, a specific exchange line or a nominated trunk group. If automatic line selection is disabled, the user must first press a resource key to obtain dialtone.