TM 1-1510-225-10
3B-184
Figure 3B-142. TTC-920 Transponder/TCAS Control
Table 3B-103. TTC-920 Transponder/TCAS Control Switch Descriptions
SWITCH
LEGENDS
FUNCTION
1
Altitude Enable Switch
ALT / OFF
Enable altitude reporting on transponder.
2
Transponder
Enable
Switch
1 / 2
Enables #1 or #2 transponder.
3
Fail Indicator
ATC FAIL
Indicates failure in transponder, control panel,
antennas, or air data system when lamp remains
lit.
4
Identification Button
IDENT
Enables transponder IDENT.
5
TCAS / ATC Mode
Select Switch
0000 through 7777, as
selected
Selects transponder code displayed in window.
6
Function Select Switch
TEST / STBY / XPDR-
TA / TA/RA
Selects indicated functions (TEST and STBY apply
to both TCAS and transponder. XPDR turns on
transponder and leaves TCAS in standby. TA
equals TA only. Other positions enable TCAS and
transponder.
