User Guide

Series III Avionics
Pilot's Guide
Page 5
CD-402B Display
Active Frequency
The upper line of the display always shows the active
frequency
Active Annunciator
…which is indicated by the Active Annunciator (the letters
ACT).
Standby Frequency
The lower line of the display shows the standby frequency.
When both frequencies are shown, rotating the
FREQUENCY KNOBS changes the standby frequency.
Transmit Annunciator
The Transmit Annunciator (the letters Tx) indicates an RF
output of the transmitter. It appears when the microphone
is keyed.
System Number
The System Number indicates that this display is for COM
System 2 (when more than one system is installed). The
number 1 indicates that this display is for COM System 1
(when more than one system is installed).
If only one COM System is installed or if this Control
Display Unit controls COM 3 in a three-radio system, the
display shows a blank instead of 1 or 2.
FAIL 1
in the lower line of the display indicates a System
failure. Neither transmitter nor receiver is operative.
FAIL 2
in the lower line of the display indicates a
Transmitter only failure. This is displayed only when the
microphone is keyed. The receiver is still operative unless
FAIL 1
is displayed with the microphone not keyed.