Comtech EF Data SDM-2020 - Manual (Page 100)

7-1
Chapter 7. RS-422 PARALLEL/SERIAL
INTERFACE
7.1 G
ENERAL
This interface operates at RS-422 signal levels. It accommodates a variety of MPEG-2
framing formats and EIA-530 serial data.
7.1.1 A
PPLICABLE
D
OCUMENTS
TM1449 Interfaces for CATV/SMATV Headends and Similar Professional Equipment
TIA/EIA-644 Telecommunications Industry Standard, Electrical Characteristics Of Low
Voltage Differential Signaling (LVDS) Interface Circuits (originally Standards
Proposal SP-3357)
RS-422 Electrical Characteristics of Balanced Voltage Digital Interface Circuits
EIA-530 High Speed 25-Position Interface for Data Circuit - Terminating Equipment
7.1.2 D
ESCRIPTION
The RS-422 interface has two data connectors and an auxiliary connector supporting
various operating modes.
• J3 Parallel/Serial DVB Connector (25-pin D, female):
• Parallel mode – In this mode, the interface behaves like a DVB parallel
synchronous interface, but with RS-422 levels. The input is at the byte
rate.
• Serial mode – An alternate form of operation is possible, where the MSB
is used for serial input at the bit rate.
• J4 Serial EIA-530 Connector (25-pin D, female):
• Serial mode only – RS-422 levels with pinout and operation per EIA-530
at a serial clock rate.