129. OPERATING CONTROLS AND INDICATORS.
used to enable the transponder set to process Mode 4 inter-
rogations. The handle of this switch is designed to permit
130. The operating controls and indicators and their panel
recognition by touch. Also, to prevent accidental setting of
markings, shown in Figure 13, are the same on all the
the switch to OUT, the handle must be pulled outward be-
transponder set controls. The functions of these controls
fore it can be lowered to the OUT position. A three-position
and indicators are described in Table 11.
toggle switch selects Mode 4 monitoring and the monitoring
method. The AUDIO position selects both audio and reply-
light monitoring; the LIGHT position selects reply-light mon-
itoring only; and the OUT position turns off the monitor-
ing circuits. A knob-actuated rotary switch is used for Mode
4 CODE selection. To prevent the control from being acci-
dentally set to the ZERO position, the knob must be pulled
out before the switch can be turned to ZERO. The switch
also includes a spring-return which automatically returns the
switch and knob to the A position from the HOLD position.
128. INDICATOR LIGHTS. Both the TEST and REPLY
indicator lights are press-to-test types. Operation of the lamps
can be checked by pressing the cap in and observing that the
lamp lights, Also, the light may be dimmed by turning the
cap clockwise. The TEST light is associated with the trans-
ponder set test circuits, while the REPLY light is part of the
Mode 4 control circuits.
Figure 13. Operating Controls and lndicators
TABLE 1-1. OPERATING CONTROLS AND INDICATORS
CONTROL OR INDICATOR
Turns transponder set on and off, selects receiver sensitivity, and selects emer-
Removes power from transponder set and transponder computer.
Enables transponder receiver and computer; disables transponder
Places transponder set in operation at reduced receiver sensitivity.
Places transponder set in operation at normal receiver sensitivity.
Causes automatic transmission of emergency reply signals to Mode
1, 2, or 3/A interrogations only, regardless of mode switch settings
(not affected by Mode C or 4 interrogations).
ON position selects Mode 1 operation of transponder set; TEST position selects
Mode 1 test operation; OUT position turns off Mode 1 operation.
ON position selects Mode 2 operation of transponder set; TEST position selects
Mode 2 test operation; OUT position turns off Mode 2 operation.
ON position selects Mode 3/A operation of transponder set; TEST position selects
Mode 3/a test operation; OUT position turns off Mode 3/A operation.
ON position selects Mode C operation of transponder set; TEST position selects
Mode C test operation; OUT position turns off Mode C operation.
Select and indicate Mode 1 two-digit reply code number.
MODE 1 Reply-code
Selector Switches (2)
Select and indicate Mode 3/A four-digit reply code number.
MODE 3/A Reply-code
Selector Switches (4)
IDENT position selects identifier pulse; MIC position permits selection of identi-
fier pulse when microphone keying switch is closed; OUT position turns off iden-
tifier pulse circuit.