(d)
An identification switch (IDENT) which causes the active transponder to transmit a special pulse identifier with the next ground station interrogation.
(e)
An altitude reporting switch (ALT RPTG OFF/ON) which disables or sets the altitude reporting function on the active transponder.
3. ATC Transponder (Fig. 1)_______________
A. The ATC transponders are located on the E2 electronic equipment rack. The No. 1 transponder is located on shelf E2-2. The No. 2 transponder is located on shelf E2-4.
B. The active ATC transponder transmits a coded reply when it is
interrogated by an ATC ground station.
(1) Both transponders are identical to each other. Each transponder has the following switches and indicators:
(a)
A green PASS indicator light which comes on when a transponder self-test is successful.
(b)
A red FAIL indicator light which comes on when a transponder self-test detects a failure.
(c)
A red UPPER ANT indicator light which comes on during a self-test when the upper antenna impedance is incorrect.
(d)
A red LOWER ANT indicator light which comes on during a self-test when the lower antenna impedance is incorrect.
(e)
A red ALT indicator light which comes on when the altitude input source indicates a barometric altitude failure.
(f)
A red CTL indicator light which comes on when there is a failure of the control input.
(g)
A TEST switch which starts a transponder self-test.
