Product specifications

CRS-170A L-Band 1:1 Redundancy Switch Revision 3
Modem and Switch Configuration MN/CRS170A.IOM
3.2 Configuring CDM-625s for 1:1 Redundancy
Because the CDM-625 can detect if it is connected to a 1:1 redundancy system, the steps required
to configure both modems is minimal. Before connecting the modems to the CRS-170A, follow
the below procedures if applicable. If terrestrial data is not Ethernet and CnC will not be used,
then no modem 1:1 redundancy configuration is needed.
3.2.1 IP Redundancy Configuration
If the terrestrial data type is Bridge-mode Ethernet, then unique IP addresses that are on the same
subnet must be entered into both modems. Using the CDM-625 front panel menu, the procedure
to do this is as follows:
1. From the top-level SELECT: menu, navigate each menu level using the ◄► arrows and
ENTER key until the Address/Range screen appears:
SELECT: Configuration Æ IP Æ Address/Range
Ethernet IP Address/Range:
192.168.001.002/24 (34)
2. The two CDM-625s will now need an Ethernet connection to each other through a Layer 2
switch or hub – preferably an L2 switch; see Chapter 4. CABLES AND CONNECTIONS
for further information.
3.2.2 Carrier-in-Carrier
®
Redundancy Configuration
If Carrier-in-Carrier
®
(CnC) is utilized, the CnC control setting must be set to Redundancy
mode. Using the CDM-625 front panel menu, the procedure to do this is as follows:
1. From the top-level SELECT: menu, navigate each menu level using the ◄► arrows and
ENTER key until the PMSI control mode screen appears
SELECT: Configuration Æ CnC Æ PMSI-control
CnC PMSI mode: Redundancy
(Idle, Redundancy, Talk, Listen) (v)
From the CnC PMSI mode screen, use the ▲ ▼ arrow keys to select Redundancy, and then
press ENTER.
2. The two CDM-625s will now need to be connected together via use of a 1:1 PMSI cable
(note that this cable bypasses the CRS-170A). See Chapter 4. CABLES AND
CONNECTIONS for further information.
The Pre-Mapped Symbol Interface (PMSI) is a function associated with DoubleTalk
®
Carrier-in-Carrier
®
that 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 this 1:1 redundancy, the PMSI
is an RS-485 multi-drop bus system where one device transmits and the other device on the
multi-drop bus is configured to receive.
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