Comtech EF Data CDM-600/600L - Manual (Page 70)

CDM-600/600L Open Network Satellite Modem Revision 3
Rear Panel Connector Pinouts MN/CDM600L.IOM
3–10
3.4.5 P5B Alarms Connector, DB-15M
The 15-pin Type ‘D’ male (DB-15M) P5B Alarms connector provides the
user with access to the Form-C relay contacts, which indicate the fault
status of the unit. These are typically connected to an external fault
monitoring system, often found in satellite earth stations. In addition, the
receive I and Q demodulator samples are provided on this connector. Connecting these signals to
an oscilloscope in X,Y mode will provide the receive signal constellation diagram, which is a
useful diagnostic aid. A pin also is provided which can mute the transmit carrier. This requires
that the pin be shorted to ground, or a TTL ‘low’, or an RS-232 ‘high’ signal be applied.
As an aid to antenna pointing, or for driving step-track equipment, an analog AGC signal is
provided on Pin 2 of this connector.
P5B Alarms Connector (DB-15M)
Pin # Signal Function Name
8
15
7
RX Traffic (De-energized, Faulted)
RX Traffic (Energized, No Fault)
RX Traffic RX-NC
RX-NO
RX-COM
14
6
13
TX Traffic (De-energized, Faulted)
TX Traffic (Energized, No Fault)
TX Traffic TX-NC
TX-NO
TX-COM
5
12
4
Unit Fault (De-energized, Faulted)
Unit Fault (Energized, No Fault)
Unit Fault UNIT-NC
UNIT-NO
UNIT-COM
11
3
RX I Channel (Constellation monitor)
RX Q Channel(Constellation monitor) RX-I
RX-Q
10 No Connection N/C
2 AGC Voltage (Rx signal level, 5 to 8 volts) AGC
9 EXT Carrier OFF EXT-OFF
1 Ground GND