Specifications

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Cisco 7100 Series VPN Router Installation and Configuration Guide
78-6341-03
Chapter 3 Installing a Cisco 7100 VPN Series Router
Connecting to the Network
Connecting the Cisco 7120-4T1 and Cisco 7140-8T
The four T1 ports on the Cisco 7120-4T1 and eight T1 ports on the Cisco 7140-8T and adapter cables
allow a high density of interface ports, regardless of the size of the connectors typically used with each
electrical interface type. All ports use an identical 60-pin D-shell receptacle that supports all interface
types:
• EIA/TIA-232
• V. 3 5
• EIA/TIA-449
• X.21
• EIA-530
Each port requires a serial adapter cable, which provides the interface between the high-density serial
port and the standard connectors that are commonly used for each electrical interface type.
The adapter cable determines the electrical interface type and mode of the port (data terminal equipment
[DTE] or data communications equipment [DCE]) to which it is connected.
At system startup or restart, the network processor polls the interfaces and determines the electrical
interface type of each port (according to the type of cable attached). However, it does not necessarily
repoll an interface when you change the cable. To ensure that the system recognizes the new interface
type, use the shutdown interface command before replacing the cable. After you replace the cable, use
the no shutdown interface command to enable the interface.
To connect a serial cable to the network, use the following procedure:
Step 1 Attach the appropriate serial cable directly to the receptacle on the router and tighten the strain-relief
screws. (See .)
Step 2 Attach the network end of the serial cable to a data service unit (DSU), channel service unit (CSU), DTE,
or other external synchronous serial equipment and tighten the strain-relief screws.