Revision A
T-48 90 008 026
2-14
2.11.4 Mode S Manual Sequence of Transponder Tests
By selecting the manual sequence of Mode S tests, the operator will be able to view the results of each test,
repeat them as necessary, test the function of the transponders “IDENT” function, and display pulse width,
pulse spacing and data pulse measurements.
To commence the manual sequence, the operator must press the
TEST
button after the Test Set has verified
a RF signal and the first test display is shown on the front panel of the Test Set.
The T-48 has determined a Mode S equipped transponder is being
received. To continue testing, the operator must depress the “
TEST
”
button.
MODE 3A test initialized. Framing pulse width, data pulse, and
spacing are also tested but are not displayed unless a failure was
detected.
Mode 3A test complete. Display indicates the transponders 4096
Octal code (1234) and receiver efficiency (100%) as a percentage.
To test the transponder “
IDENT
” function, press the appropriate button in the aircraft or on the Test
Fixture. Toggle
STORE/REPEAT
. The MODE 3A test will be repeated. “
IDENT
” should appear on the
display indicating the receipt of the
SPI
pulse.
“
IDENT
” indication displayed confirming a
SPI
pulse was transmitted
following the last framing pulse.
To advance to the next test, the
TEST
button must be pressed.
MODE 3C test initialized.
The transponders reported altitude in feet (in 100 ft. increments) and
receiver efficiency as a percentage.
TEST
button pressed to advance to next test.
MODE 3A ALL CALL test initiated. Test Set transmits a MA All Call.
MODE S XPDR COM/AB
INTERROGATE TO TEST
MODE 3A & SLS
TESTING . . .
MODE 3A
1234 100% REPLY
MODE 3A IDENT
1234 100% REPLY
MODE 3C
TESTING . . .
MODE 3C
10,000FT 100% REPLY
MODE 3A ALL CALL
TESTING . . .
