MXS System Description and Installation Manual
UM06945
© Sagetech Avionics 2022 Proprietary Confidential
Page 29 of 56
•
The communication ports (
Com0 and Com1
) can be configured as either a RS-232 or RS-422 serial
bus. Selecting the serial communication port bus type is controlled by the state of
Com0-Mode
and
Com1-Mode
signals. The Com-Mode pins will select RS-422 if left open, if grounded they will
configure the ports for RS-232. A truth table based on the state of Com0-Mode and Com1-Mode
is provided in Table 6-2
•
Priority SQUAWK
is a ground/open discrete input to the MXS. When this pin is grounded the
SQUAWK code will be automatically set to a preprogrammed SQUAWK code that is set in the Civil
Setting message and stored in NVM. When the Pin is open the SQUAWK, code defaults to the
value set in the operating message.
•
At least one COM port or the Ethernet port must be used for the Host Interface.
•
The
ethernet
interface of the MXS only supports a point-to-point connection.
•
Mutual Suppress
is designed to connect to an aircraft’s bidirectional suppression bus. Mutual
suppression bus is used to desensitize L-Band receivers and block L-Band transmitters when
another on-board L-Band equipment is transmitting. This prevents interferences from own-ship
L-Band transmitters. It is typically used when aircraft equipage includes Transponders, TCAS
and/or DME. MXS stops transmitting and receiving when Mutual Suppression line is driven to high
(18V-70V) by an external source. The MXS will return to normal operation within 15 microseconds
following the suppression pulse. In the case of a continuously high suppression bus, MXS will
automatically return to the unsuppressed state after 12-25ms.
•
The nominal mutual suppression output pulse amplitude is 28V +/- 1V. Rise time of the output
mutual suppression pulse will be no less than 20V/μs and decay time will be no less than 10V/μs.
The suppression bus driver can drive a load between 300Ω to 2.2kΩ, however in the case that th
e
mutual suppression bus is loaded with a resistance of 2.2kΩ the maximum capacitance to
maintain a 10V/μs decay time must be 800pF or lower
.
Table 6-1 Pin-Out Definition
Pin
Number
Signal
Direction
Signal Char.
1
Reserved
No Connect
-
2
Reserved
No Connect
-
3
GND
5
Ground
4
Reserved
No Connect
-
5
Reserved
No Connect
-
6
Reserved
No Connect
-
7
Reserved
No Connect
-
8
Reserved
No Connect
-
9
GND
Ground
10
Pin 10 - 35 short
Bi-Directional
Pass-through
5
MXS has a common ground, all pins are internally connected. Ideal installation utilizes all ground pins to provide best
ground return path.
