Comtech EF Data CRS-170A User Manual

Page 53

CRS-170A L-Band 1:1 Redundancy Switch

MN/CRS170A.IOM

Modem and Switch Configuration

Revision 13

4–5

4.2.2 Configure CDM-625/A Carrier-in-Carrier® for Redundancy Operation

The Pre-Mapped Symbol Interface (PMSI) is associated with DoubleTalk

Carrier-in-Carrier

. It

permits the modulator in a selected unit to provide a direct copy of its output (the outbound

interferer) to the second modem. The other modem may then choose to take the PMSI signal

and use it for its own CnC reference. In 1:1 redundancy, the PMSI is an EIA-485 multi-drop bus

system where one device transmits and the other device on the multi-drop bus is configured to

receive.

If you use Carrier-in-Carrier

(CnC), you must configure the CnC control setting to Redundancy

mode using the CDM-625/A front panel menus.

Do these steps to configure the CnC control setting for CDM-625/A 1:1 Redundancy:

Step Task

From the modem front panel menu – Use the ◄► arrow and ENTER keys to select the PMSI

control mode menu:

SELECT: Configuration  CnC  PMSI-control

CnC PMSI mode: Redundancy

(Idle, Redundancy, Talk, Listen) (

)

Use the ▲ ▼ arrow keys to select Redundancy, and then press ENTER.

You will now need to connect the two modems together via use of a 1:1 PMSI cable (note that

this cable bypasses the CRS-170A).

• Chapter 5. CABLES

AND

CONNECTIONS

• Appendix A. CABLE DRAWINGS