Comtech EF Data SDM-2020 - Manual (Page 134)

SDM-2020 Satellite Demodulator Revision 4
RS-422 Data Interface MN/SDM2020D.IOM
7–8
7.3.1.3 Auxiliary, J5
This port provides for other modem-specific signals not otherwise defined for either or
both of the two data connectors.
7.3.1.3.1 Connector Pinout, J5
The connector is a sub-miniature, 9-pin, female D connector, with threaded jack nuts
(refer to Table 7-4 for connector pinout).
Differential pairs are RS-422 compatible.
Note: The sense of differential signal pairs is a logic “1” when “B” is positive with
respect to “A.”
Single-ended signals (MF and DF fault signals) are open-collector where:
V
oh
=12V max. And V
ol
=0.5V max. @ I
ol
=8 ma.
A pull-up resistor, external to the equipment, is required.
The fault signals, MF and DF, operate as follows: A fault is indicated by an “OFF”
collector (high) and OK status is indicated by an “ON” collector (low).
Table 7-4. Auxiliary Connector Pinout (J5)
Pin # Signal Function Name Type Comment
1 GND Signal Ground
2 Demod Fault Indicator DF O Demodulator Summary Fault
Redundancy switch application
3 Send Timing ST-A O Modulator
SCT for terrestrial synchronization
4 N/C
5 Not Used
6 Mod Fault Indicator MF O Modulator Summary Fault
Redundancy switch application
7 Carrier Detect /CD O Demodulator
8 Send timing ST-B O Modulator
SCT for terrestrial synchronization
9 Not Used