User's Manual

SECTION III OPERATION
SM 7063 07/97 3-25
3.12.2 Rear-to-Front Communications Failure (R TO F FAILURE)
If no messages are received from the End Unit for a period of approximately 5 minutes 41 seconds, the
CDU will flash the
R TO F FAILURE
annunciator 5 times accompanied by beeps from the sonalert and
then remain ON. The
Brake Pressure Display
will indicate 3 dashes
“ - - - “
since the pressure
reading is now unknown.
The
R TO F FAILURE
annunciator will remain lit until a valid message is received from the matching
End Unit. As soon a message is received, the alarm will be reset and the annunciator will turn OFF.
Note, Rear-to-Front Communications problems may be caused by:
Long tunnels
Wrong ID Code entered into the CDU
Discharged battery in the End Unit
Faulty End Unit antenna or transmitter circuitry
Faulty CDU antenna or receiver circuitry
3.12.3 Front-to-Rear Communications Failure (F TO R FAILURE)
A Front-to-Rear Communications Failure Alarm can be caused by one of the following conditions:
No confirming message has been received from the End Unit 15 seconds after the EMERGENCY
switch was activated.
No confirming message has been received from the End Unit within approximately 6 minutes and 30
seconds after an Automatic Communication Test from the CDU.
When either of the above conditions occur, the CDU will flash the
F TO R FAILURE
annunciator 5
times accompanied by beeps from the sonalert and will then remain ON.
If a confirming message is received in response to a press of the
COMM ARM
key (manual
communications test) or after an Automatic Communication Test, the
F TO R FAILURE
annunciator
will turn OFF.
Note, Front-to-Rear Communications problems may be caused by:
Long tunnels
Wrong ID Code entered into the CDU
Discharged battery in the End Unit
Faulty End Unit antenna or receiver circuitry
Faulty CDU antenna or transmitter circuitry