Pmsi Interface Example - Comtech EF Data CRS-170A Installation And Operation Manual

CRS-170A L-Band 1:1 Redundancy Switch
Cables and Connections
5.3.2.3

PMSI Interface Example

The Pre-Mapped Symbol Interface (PMSI) is an EIA-485 point-to-point bus system where one device
transmits, and the other device on the bus is configured to receive. It is a function associated with
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DoubleTalk Carrier-in-Carrier
copy of its output (the outbound interferer) to the Offline modem in a 1:1 pair. The Offline modem then
takes the PMSI signal and uses it for its own CnC
You must take specific configuration steps to enable CnC
you can make any switch configurations, This ensures proper operation of the pair within a configured
CRS-170A 1:1 Redundancy System.
Chapter 4. MODEM
Use of PMSI requires that you connect and secure the CDM-625A or CDM-625 Multi-drop CnC
Cable CA-0000276 (2X DB-9M, 1') between the Redundant Modem and the Traffic Modem using CnC.
See Figure 5-17.
The CA-0000276 Multi-Drop CnC PLUS 1:1 Cable bypasses the CRS-170A L-Band 1:1
Redundancy Switch.
CEFD Part No.
CA-0000276
Figure 5-17. CDM-625A or CDM-625 PMSI 1:1 Example
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(CnC ) that permits the modulator in a selected unit to provide a direct
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reference.
SWITCH CONFIGURATION
AND
Qty Description
CDM-625A or CDM-625 Data Cable – Shielded, Multi-drop CnC
1
DB-9M, 1'
5–20
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in your CDM-625A or CDM-625 1:1 pair before
MN/CRS170A.IOM
Revision 14
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Plus 1:1
Plus, 1:1, (2X)
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