For IP Office Release 7.0+ the system mode can be changed between key system mode and PBX system mode. The selected mode affects a number of controls, mainly around the making of outgoing calls and the routing of incoming calls.

The default mode that the system adopts depends on the type of System SD card fitted to the system. Systems with a PARTNER, Norstar or IP Office U-Law card default to key system mode. Systems with an IP Office A-Law card default to PBX system mode.

Key Mode vs PBX Mode - Quick Summary

Key Mode

PBX Mode

The first 2 programmable buttons are used as intercom buttons.

Internal calls are made and answered using the intercom buttons.

External calls are made and answered using line appearance buttons.

The line used for outgoing external calls is determined by the line button pressed.

Automatic line selection defaults to the analog lines present and then the 2 intercom buttons.

The first 3 programmable buttons (2 on ETR phones) are used as call appearance buttons.

Internal calls are made and answered using the call appearance buttons.

External calls are made and answered using the call appearance buttons.

The line used for outgoing external calls is determined from the number dialed.

Automatic line selection defaults to the 3 call appearance buttons (2 on ETR phones).