Mocomtech CRS-300 - Manual (Page 100)

CRS-300 1:10 Redundancy Switch Revision 16
Cables and Connections MN/CRS300.IOM
4–40
4.6 CDM-Qx/QxL Modem Connections
If adding a modem to an operating 1:N system, care needs to be taken to not interfere with the
existing traffic. The cabling, power-up sequence and COMs connections must be correct to avoid
contention in the system from the modem Tx carrier. This information is detailed in
Chapter 7.4.5 (CONFIG) ACTIVE MODEMS .
As shown in Figure 4-18 through Figure 4-21, the CA/WR12069-1 Control Y-Cable provides
fault information from the modem and IF-Mute to the modem, and is therefore always required.
4.6.1 RMI/TMI Limitations and Considerations
Because the CDM-Qx/QxL redundant modem can only support one type of data interface, the
TMIs cannot be mixed within the same CRS-300 Redundancy Switch.
IMPORTANT
Depending on the traffic data type, the appropriate jumper settings are provided on
the TMI to ensure proper operation for EIA-422 with RTS/CTS, DTR/DSR signal
using the CRS-316 TMI, or for HSSI with CA/TA signals using the CRS-336 TMI.
Refer to Chapter 4. MODEM, TMI, AND SWITCH CONFIGURATION for this important
configuration information.
4.6.2 EIA-485 Connections – CRS-300 to Modems
An EIA-485 Multi-drop cable provides the communication path between the Switch and the
modems. There are two types of EIA-485 Multi-drop cable available: a standard CA/WR11417-1
shielded cable to guard against EMC (Electromagnetic Compatibility) concerns, and an optional
CA/RB11423-1 ribbon cable. Both are available from Comtech EF Data.
Refer to Figure 4-16 to connect the EIA-485 multi-drop cable between the Switch and the
modems as follows:
• Connect and secure (1) CA/WR11418-1 EIA-485 terminator on each far-end DB-9F
connector of the appropriate EIA-485 multi-drop cable (the standard CA/WR11417-1
shielded cable or the optional CA/RB11423-1 ribbon cable).
• Connect and secure one end of the Null Modem Cable CA/WR11419-1 to the DB-9F
connector labeled “485 Pass-Through” on the CRS-300’s CRS-230 System Controller.
• Connect and secure the EIA-485 multi-drop cable to all CDM-Qx/QxL modems and
to the DB-9M connector on the Null Modem Cable.