What dial codes (feature codes) are supported?

Call Forwarding

See here for turning call forwarding on or off

Check Voicemail

See here for accessing voicemail (yours & others’).

Call Parking

See here for details on call parking.

Direct Extension Pickup

To pick up any extension that is ringing, dial *87 + extension number of the device ringing

Intercom

To instantly connect in hands-free mode, dial *0 + the recipient’s extension number. See here for details.