Comtech EF Data SDM-2020 - Manual (Page 167)

11–1
Chapter 11. G.703 Interface
This section describes the plug-in G.703 Data Interface used with the SDM-2020
Demodulator.
11.1 G.703 Data Interface (PL/6168-1)
The G.703 interface provides connection to the standard plesiochronous digital hierarchy
(PDH). With this interface the modulator or demodulator operates at a fixed rate of 6.312,
8.448, 32.064, 34.368, 44.736, or 51.840 Mbps. An auxiliary connector provides open
collector fault lines for reporting a failure to external equipment like a redundancy
switch. The G.703 signals connect to the module’s BNC female connectors, and the
signals supported are SD, RD and EXT (external) Clock.
This data interface also contains a receive buffer that provides 0 (bypass) to 32 ms in 2
ms steps. The input clock to the receive buffer is always from the satellite, but the output
of the buffer is selected from the satellite clock, EXT Clock or a clock derived from SD.
A separate auxiliary connector provides modulator and demodulator fault status for
connection to a redundancy switch or other equipment.
IMPORTANT
This module is used in either the SDM-2020 Modulator or Demodulator.
11.1.1 Applicable Documents
Applicable documents, as referenced herein, include:
• ITU-T G.703, Physical/Electrical Characteristics Of Hierarchical Digital
Interfaces