User Manual Part 2

OPERATING MANUAL
2B-09-00
Page 67
Nov 15/02
DIGITAL AUTOMATIC FLIGHT CONTROL SYSTEMS
5. Operational Modes
The audio panel operates in one of five of modes:
D Normal Operational Mode.
D Software Loading Mode
D Backup (BKUP) Mode.
D Configuration Mode
D APC Test Mode
A. Normal Operational
During normal operation, the audio panel consists of 30 audio channels some of which are
dedicated and others which can be customized by the pilot. The 30 channels are used to
support the following functions during Normal mode operations:
D Radio Receiver
D Radio T ransceiver
D Intercom
D CVR
D PA
D Telephony
D SELCAL
The aural warning function is supported by the audio panel based upon inputs from the NIM.
The audio panel controls audio and transmission to the following:
D Two dedicated VHF channels
D Eight auxiliary transceiver channels
D Five intercom channels
D One maintenance intercom channel
D Dedicated navigation audio channels
D Four auxiliary navigation audio channels
D A single CVR channel.
The dedicated navigation receivers are the VOR, VIDL, ADF, Marker (MKR), DME, and MLS.
B. Radio Receiver
Radio receiver audio channels support radio reception only (i.e. VHF NA V, ADF, MKR, MLS
and DME). These channels receive digitized, multiplexed audio data from the MRC over the
digital audio busses. The audio panel decodes, filters, applies gain to the selected digitized
channels, converts the samples to analog audio, and outputs the analog audio to the
Headphones, Speakers, and CVR.
C. Radio Transceiver
Radio transceiver audio channels support reception and transmission of audio on both the
dedicated and auxiliary transceiver channels. The received audio from these transceivers
is received on the digital audio buses from the MRC radio cabinet. The audio panel decodes,
filters and amplifies/attenuates, convert the samples to analog audio, and outputs the analog
audio on the Headphones, Speakers and CVR output ports.
The transmitted audio is sent to the MRC radio cabinet over the MIC bus. The audio
originating from the selected microphone is sampled, digitized, filtered, amplified/attenuated,
and multiplexed onto the MIC bus. Additionally, a sidetone is created for feedback to the
crewman either through the headset or through the speakers on the flight deck or both.