CRS-300 1:10 Redundancy Switch Revision 16
Modem, RMI/TMI, and Switch Configuration MN/CRS300.IOM
5–4
5.2.4.2.1 CDM-625 Redundancy Configuration with Carrier-in-Carrier®
If Carrier-in-Carrier® (CnC) is utilized with any CDM-625 traffic modem, special
configuration steps must be taken to ensure proper operation of the modem(s) within a configured
1:N Redundancy System.
Before any configurations can be made, refer to Figure 4-9 and the instructions found on Page
4-22 in Chapter 4. CABLES AND CONNECTIONS to connect and secure the PMSI Multi-
drop CnC Plus Cable CA-0000275 (<11X> DB-9M, 8.25’) between the Redundant Modem and
any Traffic Modem(s) using CnC.
I
MPORTANT
The CA-0000275 cable bypasses the CRS-300 1:10 Redundancy Switch.
Once all CnC-enabled modems have been interconnected with the PMSI Multi-drop Cable, the
user must then configure each CnC-enabled modem via the modem’s front control panel:
From the CDM-625 top-level SELECT: menu, using the ◄► arrows and ENTER keys,
navigate each menu level until the PMSI control mode display screen appears:
SELECT: Configuration Æ CnC Æ PMSI-control
Select: Configuration Test Monitor
Info Store/Ld Utility ODU FAST (34)
CONFIG: All Mode Tx Rx Clocks D&I
CnC EDMAC Misc Mask Remote IP (34)
Carrier-in-Carrier: Mode Freq-Offset
Search-Delay PMSI-control (34)
CnC PMSI mode: Redundancy
(Idle, Redundancy, Talk, Listen) (v)
From the PMSI mode display screen, use the arrow keys to select Redundancy, then press
ENTER.
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 one or many other modems. The other modem(s) may then choose to take
the PMSI signal, and use it for its own CnC reference. The PMSI is an EIA-485 multidrop bus
system where one device transmits, and all other devices on the multi-drop bus are configured to
receive.
This configuration step must be repeated for every CnC-enabled CDM-625
within the configured redundancy system.