The interphone/intercom system is used by persons to speak to each other between different areas on the aircraft. This includes communication between pilots, pilot/ground crew, and ground crew to ground crew. The audio panel which controls the audio integrating system also controls the interphone system.

The interphone system has the components that follow:

• Flight Compartment Loudspeakers
• Audio Panels
• Radio Transmit Switches (push-to-talk (PTT) switches)
• Hand Microphones
• Service Interphone Unit (Intercom Panel) in the Main Avionics Compartment
• Service Interphone Unit (Intercom Panel) in the Aft Equipment Compartment
• Pilot's Headset Jacks Panels
• Audio Jacks on the External-Communications Servicing-Connection Panel
• Audio Jacks on the Aft Service Control Panel

---

Two flight compartment loudspeakers supply the audio outputs for the interphone system in oxygen mask mode, and the audio integrating system. These loudspeakers are flange-mounted in the overhead panels above the pilot's seats.

---

The audio panels are attached by Dzus fasteners in the center pedestal. They supply integrated control of all audio functions in the aircraft. The controls that follow are related to the interphone system as well as the audio integrating system:

INT (interphone) control

The INT control is a rotary and push-in type switch that controls the interphone function. The turn knob only adjusts the headset audio level when in interphone function. Interphone function is armed when the INT switch is latched out and disarmed when the switch is latched in. The INT switch also receives audio signals from other audio panels and from the audio jacks on the maintenance/services panels. The interphone function uses the H'MIC (hot microphone) or PPT (push-to-talk) modes. Interphone audio is usually not available through the cockpit speakers until oxygen mask microphone is set.

ST (side tone) control

The ST control is a rotary and push-in type switch that controls the sidetone level and on/off operation of the cockpit speaker. When the ST switch is latched in, the related loudspeaker is off. When released out, the loudspeaker is on. The turn knob is used to control unwanted feedback from a loudspeaker into an active microphone.

H'MIC (hot microphone) control

The H'MIC control is a push-in type switch. When pushed in, the switch connects one of the different microphones to the interphone PTT function. When released (out) this hot mic function is off.

SPEAKER control

The SPEAKER control is a rotary switch that adjusts the volume level of a flight compartment loudspeaker. The volume of the audio warnings is not controlled by this switch.

HEADPHONE control

The HEADPHONE control is a rotary switch that adjusts the volume level of all signals into a headset. The volume of the audio warnings is not controlled by this switch.

MIC/MASK control

The MIC/MASK selector is a rotary and push-in type switch that makes selection between a boom microphone (MIC) and an oxygen mask microphone (MASK). When the selector is latched in MIC is set. When the selector is latched out MASK is set. When in MASK function, the interphone audio volume from the loudspeakers can be adjusted with the MIC/MASK rotary switch. The ST/SPKR push-in switch does not disarm MASK interphone audio from the speakers.

---

The radio transmit (R/T) switch connects the related active microphone to the intercom/interphone system or a radio transmitter. This push-to-talk (PTT) switch is on the control wheel of each control column in the flight compartment.

---

The microphone is a electet-condenser type, hand-held unit. The microphone has a PTT switch and an attached cable with plugs. There are two microphones in the flight compartment, each installed on the control column.

---

The service interphone units are intercom panels that supply an audio interface between the main avionics compartment, the aft equipment compartment, the flight compartment, and the remaining interphone system. Each unit has a headphone jack and a microphone jack.

---

Component Location Index
IDENT	DESCRIPTION	LOCATION	IPC REF
AP50	EXTERNAL-COMMUNICATIONS SEVICING-CONNECTION PANEL	ZONE(S) 121	23-40-05 [ GX ] [ GXRS ] [ G5000 ]
A197/A198	FLIGHT COMPARTMENT LOUDSPEAKERS	ZONE(S) 221/222	23-51-01 [ GX ] [ GXRS ] [ G5000 ]
-	FLIGHT COMPARTMENT LOUDSPEAKERS	ZONE(S) 221/222	23-51-01 [ GX ] [ GXRS ] [ G5000 ]
A8/A9/A215	AUDIO PANELS	ZONE(S) 221/222	23-51-05 [ GX ] [ GXRS ] [ G5000 ]
A215	AUDIO PANEL 3 (OPTIONAL)	ZONE(S) 222	23-51-05 [ GX ] [ GXRS ] [ G5000 ]
-	RADIO TRANSMIT SWITCHES	ZONE(S) 221/222	23-51-13 [ GX ] [ GXRS ] [ G5000 ]
-	HAND MICROPHONES	ZONE(S) 221/222	23-51-17 [ GX ] [ GXRS ] [ G5000 ]
A192	SERVICE INTERPHONE UNITS	ZONE(S) 142/311	23-51-21 [ GX ] [ GXRS ] [ G5000 ]
AP44/AP45	HEADSET JACKS PANELS	ZONE(S) 221/222	23-51-29 [ GX ] [ GXRS ] [ G5000 ]
AP51	AFT SERVICE CONTROL PANEL	ZONE(S) 171	24-40-01 [ GX ] [ GXRS ] [ G5000 ]

---