Service Interphone System
The service interphone system provides intercommunication between the flight deck, Flight
Attendants, and ground personnel. Flight deck crewmembers communicate using either a
separate handset (if installed) or their related ACP and any standard microphone.
The Flight Attendants communicate between flight attendant stations or with the flight deck
using any of the attendant handsets. Anyone who picks up a handset/microphone is
automatically connected to the system. External jacks for use by maintenance or service
personnel can be added to the system by selecting the service interphone switch to ON.
Communication between flight deck and flight attendants is possible regardless of switch
position.