Unit installation

Installation RSU-503 Redundancy Switch Unit
18 Rev. 8
2.4.4 M&C (J4, J8)
The M&C connectors are used to interface with Units A and B, respectively. Included on
these connectors are:
•
Nine RS-232/485 communication pins (A to J)
•
Switch power (L)
•
Fault reporting
The M&C connectors are 26-pin circular female connectors, with the following pinouts:
Pin # Name Function
RS-232 RS-485
AGND -RX/TX
B-RX/TX
C+RX/TX
D CTS +RX/TX Clear to Send
E TD/TX Transmit Data
F RTS Ready to Send
G RD/RX Receive Data
H DSR Data Set Ready
J GND Ground
K LNA POWER 10V to LNA
L EXT POWER Input Voltage, 11V, 1A max.
M EXT FLT IN Fault Input from TWT
N Reserved
PN/C
R GND Ground
S Chassis Ground Ground
T Reserved
U UL FLT NC Fault relay input, closes with Uplink fault
V UL FLT COM Fault relay input, COMMON
W UL FLT NO Fault relay input, opens with Uplink fault
X DL FLT NC Fault relay input, closes with Downlink fault
Y DL FLT COM Fault relay input, COMMON
Z DL FLT NO Fault relay input, opens with Downlink fault
a LNA RTN Ground return from LNA
b Reserved
c Reserved
Notes:
1. Clear to Send (CTS) is tied to Ready to Send (RTS) in RS-232 mode.
2. RD/RX and TD/TX are switched in the switch in order to communicate with
the RFTs.