Comtech EF Data SDM-2020 - Manual (Page 188)

SDM-2020 Satellite Demodulator Revision 4
SMPTE-310M Data Interface MN/SDM2020D.IOM
12–6
12.1.3.4 TX and RX Terrestrial Data Interface Connector (J3, J4, and J6)
Refer to Table 12-2 for data interface input and output interface connectors.
Table 12-2. TX/RX Terrestrial Data Interface Connector
Terrestrial Data Interfaces
J3, J4 SMPTE-310M RX Data Outputs, BNC female. Both
outputs are active simultaneously.
J6 SMPTE-310M TX Data Input, BNC female.
12.1.3.5 Auxiliary Function Port
The following paragraphs describe the electrical and physical properties of the auxiliary
function port.
12.1.3.5.1 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:
Voh = 12V maximum
Vol = 0.5V maximum at Io1 = 8 mA
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).