Comtech EF Data SDM-2020, Installation And Operation Manual

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Data Interfaces SDM-2020 Satellite Demodulator
A–54 Rev.3
A.6.8 Terrestrial Interface Types
A.6.8.1 Send Data (SD), Receive Data (RD), and External Clock
Connectors J3, J4 & J6
The Send Data (SD) (J3), Receive Data (RD) (J4) and Ext. Clock (J6) connectors are all
BNC type connectors, and are terminated into 75
Ω
.
A.6.8.2 Auxiliary Functions Connector, J5
This port provides for other modem-specific signals not otherwise defined for either or
both of the two data connectors. (Refer to Table A-33).
The connector is a 9-pin sub-miniature D female, with threaded jack nuts.
Demodulator Fault (DF
)
is a single ended open collector signal, where:
Voh=12V max. and Vol=0.5V max. @ Iol=8 ma.
A pull-up resistor external to the equipment is required.
A (DF) fault is indicated by an OFF (Vout = Hi) open collector transistor and the normal
OK state is indicated by an ON transistor (Vout = Lo).
The Carrier Detect (CD) signal is a TTL output. When CD is high, it indicates the
demodulator is locked.