Intercom is the ability to send or receive auto-answered calls. A typical use case would be an announcement that you would like to make from one colleague to the other in an office environment
On the calling phone
Configure any free Function Key as type "Intercom" . Type in the extension (can be single or call group) you want to announce the call to:
On the receiving phone(s)
Configure the setting: Advanced → Behavior : Intercom Policy to "Always" and look at the following setting: answer_after_policy .
On the calling phone, press the configured intercom function key, and the phone will send an INVITE message to the extension specified. The INVITE message will contain the "Alert-Info" Header:
which is needed to force the called extension(s) to auto answer the intercom call.