Communications - General

Introduction

The communication system includes:

• Radio Communication System
• Interphone Communication System
• Selective Calling (SELCAL) System

• Cockpit Voice Recorder System
• Communication Crew Alerting System

The Communication Systems are controlled using the:

• Audio Control Panels
• Pilots Call Panel
• Control panels for individual communication radios
• 757-300 Radio Tuning Panels to tune all communication radios

Audio Control Panels

The Audio Control Panels (ACP) are used to manage the Radio and Interphone communication systems, and are installed at the Captain, First Officer and Flight Observer stations. Each ACP provides voice and identification monitoring of selected navigation aids.

Systems are monitored using headphones or speakers. Receiver volume is controlled on the ACP by rotating the knob beneath the respective receiver. A cockpit loudspeaker is provided adjacent to each pilot seat with a speaker volume control located in the centre of the speaker.

Microphones are keyed by pushing the desired ACP transmitter select switch and holding in a Push-To-Talk (PTT) switch. The PTT switches are located on:

• The Control Wheels
• The Audio Control Panels
• As installed - Any hand microphone

There is a boom microphone on the headset, a microphone in the oxygen mask and a hand microphone jack at all flight crew member stations.

The oxygen mask microphone is enabled and the boom microphone disabled when the BOOM/OXY switch on the ACP is in the OXY position. Conversely, the oxygen mask microphone is disabled and the boom microphone is enabled when the BOOM/OXY switch is in the BOOM position.

Radios