Comtech EF Data CRS-300 - Manual (Page 92)

CRS-300 1:10 Redundancy Switch MN/CRS300.IOM
Cables and Connections Revision 19
4–18
4.4 CDM-625/A Modem Connections
If adding a modem to an operating 1:N system, care needs to be taken not to interfere with the
existing traffic. The cabling and 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).
4.4.1 RMI/TMI Limitations and Considerations
With some exceptions, Traffic modems with differing data types can all be supported by the
Redundant Modem.
See Table 4-1 for the Switch RMI, TMIs, and cables that you will need to set up a proper
redundant system configuration. As shown, and regardless of driving traffic data type, the
CRS-300 1:10 Redundancy Switch uses the CRS-310 Redundant Modem Interface (RMI) for all
driving traffic configurations.
When you use the CDM-625/A in a CRS-300 1:10 Redundancy System, you may mix TMIs within
the same Switch, with some limitations: For example, while you may use the “P2” (DB-15M)
connector on the CRS-310 RMI for Balanced / Unbalanced G.703 or Quad E1 traffic, you may use
only one of these two traffic data types within the Switch TMIs. Accordingly, for a Switch that
uses any combination of the CRS-325, CRS-330, or CRS-340 TMIs for Balanced / Unbalanced
G.703 traffic, you may not install the CRS-365D TMI (for Quad E1 traffic) in the same system.
See Figure 4-9 through Figure 4-11 for graphic examples of this operational dependency; each
figure shows the Switch TMI types that you may use with the Traffic Modems.
1) The Switch TMIs feature jumpers that are pre-set to ensure proper operation
for the following traffic data:
• For EIA-422 with RTS/CTS, DTR/DSR signals using the CRS-316, CRS-320
(obsolete), or CRS-340
• For HSSI with CA/TA signals using the CRS-336
See Chapter 5. MODEM, TMI, AND SWITCH CONFIGURATION in this manual for
this important configuration information.
2) When you use the CDM-625/A in Dedicated Management Port mode, the
modem disables all four of the offline modem’s Ethernet ports unless you
configure one of the four ports as the ‘Dedicated Management Port.’
For more information, see Sect. 5.4.13.3 CONFIG: IP  Setup in the CDM-625
or CDM-625A Advanced Satellite Modem Installation and Operation Manuals
(CEFD P/Ns MN-CDM625 or MN-CDM625A).