Product specifications

CRS-170A L-Band 1:1 Redundancy Switch Revision 3
Cables and Connections MN/CRS170A.IOM
4.2.3.10 PMSI Interface Example
The Pre-Mapped Symbol Interface (PMSI) is a function associated with DoubleTalk
®
Carrier-
in-Carrier
®
(CnC) that permits the modulator in a selected unit to provide a direct copy of its
output (the outbound interferer) to the offline modem in a 1:1 pair. The offline modem will then
take the PMSI signal and use it for its own CnC reference. The PMSI is an RS-485 point-to-point
bus system where one device transmits, and the other device on the bus is configured to receive.
Refer to Figure 4-12 to connect and secure the PMSI Cable CA-0000135 (2X DB-9M, 1’)
between the Redundant Modem and Traffic Modem using CnC
.
IMPORTANT
The CA-0000135 cable bypasses the CRS-170A 1:1 Redundancy Switch.
If CnC is utilized with a CDM-625 1:1 pair, before any switch configurations can be made,
specific configuration steps must be taken with each CDM-625 to ensure proper operation of the
pair within a configured CRS-170A 1:1 Redundancy System. Refer to Chapter 3. MODEM
AND SWITCH CONFIGURATION for pertinent instructions.
QTY Part No. Description
1 CA-0000135 Data Cable – Shielded, PMSI, DB-9M, 1’
Figure 4-12. CDM-625 PMSI 1:1 Example
4–10