Comtech EF Data CRS-300 - Manual (Page 112)

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.
1) Because the Redundant Modem’s function is to replace a faulted Traffic Modem,
the Switch RMI does not have a User Data Interface.
2) Ensure that you correctly configure modem operation for Balanced or
Unbalanced G.703 data.