The intercom feature allows for a call to be placed to phones supporting the feature, and for such phones to automatically answer the call and play the audio on speaker.
To enable intercom (disabled by default), navigate to the GUI, then Start – Configuration – Advanced and Feature Codes.
Enable the Intercom Prefix feature code and change the feature code to a code that will not conflict with existing codes (e.g. *93). Apply.
The list of phones known to support Intercom and Paging include: Aastra, Grandstream, Linksys/Sipura, Mitel, Polycom, SNOM, and possibly other SIP phones. ATAs are not supported. If your phone is set to auto-answer, it should also support intercom.
The phone must be configured to support the feature. On a Snom for example, configuration would involve turning on Auto Connect Indication, setting the Auto Connect Type to Handsfree and enabling the Intercom feature.
Please contact your phone manufacturer or consult the phone manuals for specifics on configuring your phone and model for intercom support.