1.5 Assembling and Cabling The Network
1.5.5 Cable connections
The Figure illustrates the cable connections available for the various WAN types. The numbers in the following list correspond to the numbers found in the Figure, and the items explain the cable connections necessary for the various WAN types:
  • Asynchronous Connections (1) -- Asynchronous connections require RJ-11 cables that are attached from the modem line port to the telephone company jack. If you are using an external modem attached to a Cisco router, you must also use a Cisco EIA/TIA-232 cable to attach the modem to the router serial interface. The DB-60 end of the cable connects to the router. The DB-25 end attaches to the modem.
  • ISDN BRI (2) -- ISDN BRI connection interfaces require RJ-45 cables to connect the BRI interface to the ISDN network. The BRI modules and BRI WAN interface cards are available with either an S/T interface that requires an external NT1 or a U interface that has a built-in NT1.
  • ISDN PRI (North America) (3) -- Channelized T1 (CT1)/PRI modules are available with or without a built-in CSU. If you use an external CSU, attach a female DB-15 cable to the router interface. The other end of the straight-through cable attaches to the CSU, which in turn attaches to the ISDN network. Routers with internal CSU modules attach directly to the ISDN network with a standard RJ-48 connector.
  • ISDN PRI (Europe) (4) -- Channelized E1 (CE1)/PRI modules are available with balanced and unbalanced interfaces. CE1/PRI-balanced modules provide a 120-ohm E1 interface for network connections. The unbalanced modules provide a 75-ohm E1 interface for network connections. Four serial cables are available from Cisco for the CE1/ PRI module. All four cables have DB-15 connectors on the router end; they have BNC, DB-15, twin axial, or RJ-45 connectors on the network end.
  • Frame Relay (5) -- If you must establish a Frame Relay serial connection, Cisco routers support the following signaling standards: EIA/TIA-232, EIA/TIA-449, V.35, X.21, and EIA-530. Cisco supplies a DB-60 shielded serial transition cable that has the appropriate connector for the standard you specify. The router end of the shielded serial transition cable has a DB-60 connector, which connects to the DB-60 port on the router serial interface.

The other end of the serial transition cable is available with the connector that is appropriate for the standard you specify.