Specifications

Figure 2-4. Modems Installed in the Rack
Connecting to a Transmission Line
The modem cage or modem rack has different Telco options. Your version may have 16 8-pin modular jack
connectors, one for each slot in the modem cage or modem rack. It may also have an optional 50-pin mass-
termination Telco connector.
To connect your modem to a leased line using the modular jack connectors, refer to “Modular Jack Connectors,”
below. To use the 50-pin mass-termination connector, refer to “Mass Termination Connector” on page 18.
Modular Jack Connectors
The rear panel of the modem cage or modem rack has an 8-pin RJ-45 jack for each slot. After you install the modem
into a slot, connect the slot’s corresponding RJ-45 jack to a leased line.
Leased lines have four contacts: a transmit (Tx) pair and a receive (Rx) pair. For communication to occur:
 The Rx line of the modem cage or modem rack RJ-45 jack must connect to the Tx line of the other modem.
 The Tx line of the modem cage or modem rack RJ-45 jack must connect to the Rx line of the other modem.
For more information, refer to the documentation that came with your modem cage or modem rack.
Mass Termination Connector
As an option, a 50-pin mass-termination connector can be used as the Telco connection for the modem(s). For more
information, refer to the documentation that came with your modem cage or modem rack.
Connecting an RS-232 Device
The modem cage or modem rack has different RS-232 options for accepting an attached RS-232 (RTU) device.
Your version may have a female, 25-pin RS-232 connector for each slot in the modem cage or modem rack. It may
also have an optional 50-pin mass-termination Telco connector. For more information, refer to the documentation
that came with your modem cage or modem rack.
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