Comtech EF Data CRS-300 - Control and Data Connections - CRS-300 to Modems; User Data Connections

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CRS-300 1:10 Redundancy Switch MN/CRS300.IOM

Cables and Connections Revision 19

4–38

4.5 CDM-570/A, CDM-570L/AL Modem Connections

If adding a modem to an operating 1:N system, care needs to be taken not to interfere with the

existing Traffic Modem. The cabling, power-up sequence must be correct to avoid contention in

the system from the modem Tx carrier. This sequence is described in Sect. 6.2.2.5 CONFIG:

ACTIVE (Activate Modems).

Traffic modems with differing data types can all be supported by the Redundant

Modem.

4.5.1 Control and Data Connections – CRS-300 to Modems

The 25-pin Control/Data Cable CA/WR0066 provides the EIA-422/232 traffic data path and serial

communication path between the Switch and the modems. Therefore, you must alwys use this

cable, even when the data type is G.703.

The Switch TMIs (CRS-320 (obsolete) and CRS-340) feature jumpers that are pre-set

to ensure proper operation with traffic data for EIA-422

with RTS/CTS, DTR/DSR

signals. See Chapter 5. MODEM, TMI,

AND SWITCH CONFIGURATION for this

important configuration information.

See Figure 4-15 and do these steps to connect and secure the CA/WR0066 cables between

the Switch and each CDM-570/A or CDM-570L/AL:

• DB-25M connector labeled “P1” on the Switch RMI or TMI(s), to

• DB-25F connectors labeled “Data Interface” on the CDM-570/A or CD-570L/ALs.

If G.703 is the traffic data type, also do these steps to connect and secure the Data Cable

CA/WR11999-6, which you must use for either Balanced or Unbalanced G.703 Data:

• DB-15M connector labeled “P2” on the Switch RMI or TMI(s), to

• DB-15F connectors labeled “Balanced E1/T1” on the CDM-570/A or CDM-570L/ALs.

4.5.2 User Data Connections – CRS-300 to User

You must connect your traffic data from the multiplexing equipment or test data generator to

the connectors labeled “User Data Interface” on the Switch TMI(s). This interface replaces the

direct connection to the Traffic Modem’s “Data Interface” connectors.

Because the Redundant Modem’s function is to replace a faulted Traffic Modem,

the Switch RMI does not have a User Data Interface.

Ensure that you correctly configure modem operation for Balanced or

Unbalanced G.703 data.

Comtech EF Data CRS-300 - Control and Data Connections - CRS-300 to Modems; User Data Connections - CRS-300 to User