BendixKing KXP 756 User Manual
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can selectively interrogate one specific
Mode S address.
The KFS 578A Control Unit,
supplies serial data and control signals
for the MST 67A Transponder. An
optional feature allows the use of dual
MST 67A Transponders individually
selected by one KFS 578A Control
Unit. The KFS 578A is equipped with
an ARINC 429 serial data bus. The
KFS 578A may also be used in the
tandem mode(two units controlling one
R/T with each control unit displaying
the same readout).
The selected transponder is
turned on by rotating the ON/OFF
Selector knob of a KFS 578A
clockwise from the OFF position. The
selected code may then be entered as
follows: Momentarily pressing the
FL/Cursor knob steps the cursor
(indicated by the flashing digit) to the
right one digit at a time. Rotating the
FL/Cursor knob CW or CCW changes
the numerical value of the selected
digit as desired. Rotating the Function
knob to the VFR position for
approximately 3 seconds causes the
code to automatically change to the
pre programmed VFR code(usually
1200). The selected code should be
in accordance with the instructions for
IFR flight or rules applicable to
transponder utilization for VFR flight.
The VFR code can be programmed to
be any code by the following
technique:
A. Place the function selector to VFR.
B. Select the VFR code as required.
C. Push the Ident(IDT) button. or Wait
3 seconds. or Rotate the Function
switch to the desired mode.
To eliminate the possibility of
dialing through restricted reply codes,
the transmitted reply does not change
for a few seconds after the new code
is selected completely.
Caution: Never activate the
transponder with codes 0000, 7500,
7600 or 7700 selected on the control
unit. Code 7700 is selected for
emergencies, 7600 is selected for
radio failure, and 7500 for hijack.
Code 0000 is reserved.
The MST 67A incorporates a
solid state transmitter, no warm up
time is required. Therefore, any time
that the Function Selector knob is in
the ON or ALT position, the
transponder becomes an active part of
the beacon system. It is undesirable
from the Air Traffic Control system
viewpoint to be operating out of
standby while on the ground except
during the self-test mode.
The function mode as
determined by the position of the
Function Selector knob will be
displayed in the lower section of the
display area.
The Ident Button when
depressed momentarily, and then
released, holds the IDENT reply for
approximately 18 ± 2 seconds to
assure the proper reply within at least
one radar sweep. During which time
the IDT nomenclature will be
displayed. The IDENT feature is used
at the request of the traffic controller.
An external ident feature provides for
a remote mounted push button switch
to also activate the Ident reply.
When the Function Selector
knob is in the ON position, the
transponder replies to Mode A, Mode
C and Mode S interrogations but
without flight level information. With
the Function Selector knob in the ALT
position, the transponder automatically
selects the proper reply to either a
Mode A, Mode C or Mode S
interrogation transmitting flight level
information if an altitude encoder is a
part of the installation.
An automatic dimming
function adjusts the brightness of the
displayed data and nomenclature to
compensate for changes in the
ambient light level. A provision is
made in the KFS 578A to cause the