BendixKing KXP 756 - Manual (Page 27)

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The KFS 576/576A Control Unit,
supplies serial data and control signals
for the KXP 756 Transponder. An
optional feature allows the use of dual
KXP 756 Transponders individually
selected by one KFS 576/576A
Control Unit. The KFS 576A is
equipped with a King Radio 429 serial
data bus and can be integrated into a
frequency management system. The
KFS 576A 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 Function
Selector knob of a KFS 576 from the
OFF position to the SBY position or in
the case of a KFS 576A, turning the
OFF switch clockwise to the ON
position. The KFS 576A will always be
in the standby mode when it is initially
turned on. The selected code may
then be entered as follows:
Momentarily pressing the Code
Selector knob steps the cursor
(located under the first digit of the
displayed code) to the right one digit at
a time. Rotating the knob CW or CCW
changes the numerical value of the
selected digit as desired. Holding the
code selector knob pressed in for
approximately 3 seconds causes the
code to automatically change to 1200.
The selected code should be in
accordance with the instructions for
IFR flight or rules applicable to
transponder utilization for VFR flight.
On Mod 1 KFS 576 units and all KFS
576A's, the VFR code can be
programmed to be any code (usually
1200) by the following technique:
A. Place the function selector to
STBY.
B. Select the VFR code as required.
C. Push the IDT and the CURSOR
buttons simultaneously. The new
code is now programmed into
memory and will appear whenever
the cursor is pushed and held for
approximately 3 seconds.
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,
5600, 7700 selected on the control
unit. Code 7700 is selected for
emergencies, 7600 for radio failure,
and 7500 for hijack. Code 0000 is
reserved.
The KXP 756 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
reply indicator is an R located in the
upper left of the display area and
during normal transponder operation
the R will be visible as an indication of
a transmitted reply. An interrogation
will normally be processed with each
sweep of search radar which will
normally be 10-15 second intervals.
The R may light within the interval
from a second or third interrogator.
The Ident Button when
depressed momentarily, and then
released, holds the IDENT reply for
approximately 25 seconds to assure
the proper reply within at least one
radar sweep. During which time the
IDT (ident) nomenclature will be
displayed. The IDENT feature is used
at the request of the traffic controller.
An external ident feature provides for