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SDM-2020 Satellite Demodulator
A.7.3.4
TX and RX Terrestrial Data Interface Connector (J3, J4, and J6)
Refer to Table A-35 for data interface input and output interface connectors.
Table A-35. TX/RX Terrestrial Data Interface Connector
J3, J4
J6
A.7.3.5
Auxiliary Function Port
The following paragraphs describe the electrical and physical properties of the auxiliary
function port.
A.7.3.5.1
Auxiliary Interface Electrical Specification
This port provides input/output of modem-specific signals.
Single ended open collector outputs (external pull-up resistor required) provide indicated
Modulator Faults (MF) and Demodulator Faults (DF). For MF and DF, a fault is
indicated by an OFF (Vout = Hi) open collector transistor and the normal OK state
indicates an ON transistor (Vout = Lo). MF and DF are routed directly from the
modulator or demodulator respectively. The characteristics of these outputs are:
A carrier detect (CD) output signal provides an indication that the demodulator is locked.
The output is TTL compatible. CD is routed directly from the demodulator. The default
state of the CD is high when the unit is locked, but the sense will be programmable
(function provided at the system level).
A Request to Send (RTS) input is provided to allow for remote control of the modulator
transmission carrier. The ability to enable/disable control of the modulator via this signal,
as well as the signal polarity, is programmed by the user (function provided at the system
level).
Rev.3
Terrestrial Data Interfaces
SMPTE-310M RX Data Outputs, BNC female. Both
outputs are active simultaneously.
SMPTE-310M TX Data Input, BNC female.
Voh = 12V maximum
Vol = 0.5V maximum at Io1 = 8 mA
Data Interfaces
A–61
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