Smpte 310M/Ssi Data Interface; Applicable Documents; Description - Comtech EF Data SDM-2020 Installation And Operation Manual

SDM-2020 Satellite Demodulator
A.7 SMPTE-310M/SSI Data Interface
This plug-in module provides the physical and electrical interface between external
terrestrial data equipment and the demodulator. The SMPTE-310M data interface is
based on the DVB's Synchronous Serial Interface (SSI) used with the SDM-2020
Demodulator developed for video and high-speed data applications. The data is
input/output on a BNC female connector as an 800-mV signal with biphase mark
encoding. A separate auxiliary connector provides fault status.
A.7.1

Applicable Documents

Applicable documents, as referenced herein, include:
•
•
A.7.2

Description

The SMPTE 310M data interface is a plug-in module that inserts into the rear panel of the
chassis. The data interface provides a physical and electrical connection between the
external terrestrial circuit and the internal circuitry of the unit. By convention, a modem
is Data Communications Equipment (DCE) where transmit data enters the data interface
and receive data exits. The data interface has full-duplex capability but is automatically
configured for simplex-transmit or simplex-receive operation, depending upon whether it
is plugged into a modulator or demodulator chassis.
Figure A-18 shows the SMPTE 310M data interface block diagram. At a functional level,
the data interface has four I/O ports. Transmitted data by the modulator enters the
SMPTE-310M data interface at the TX input as a synchronous serial bit stream, while
data received by a demodulator is sent by the data interface at the RX outputs as a
synchronous serial bit stream. The TX and RX serial data is biphase-mark encoded. The
modem interface is byte-oriented interface with clock, data, and synchronous signals.
Finally, the auxiliary function port provides status outputs for modulator and demodulator
faults as well as input for control and transmission.
Figure A-19 illustrates the SMPTE 310M module assembly.
Rev.3
SMPTE 310M Synchronous Serial Interface for MPEG-2 Digital Transport
Stream
TM 1449, Interfaces for CATV/SMATV Headends and Similar Professional
Equipment
Data Interfaces
A–57