2-10
Cisco 2600 Series Routers Hardware Installation Guide
OL-2171-02
Chapter 2 Preparing to Install the Router
Preparing to Connect to a Network
The EIA/TIA-449 standard was intended to replace the EIA/TIA-232 standard, but it was not widely
adopted primarily because of the large installed base of DB-25 hardware and because of the larger size
37-pin EIA/TIA-449 connectors, which limited the number of connections possible (fewer than with the
smaller, 25-pin EIA/TIA-232 connector).
The network end of the EIA/TIA-449 adapter cable provides a standard 37-pin D-shell connector.
(See
Figure 2-2
.) EIA/TIA-449 cables are available as either DTE (DB-37 plug) or DCE (DB-37
receptacle).
Figure 2-2
EIA/TIA-449 Adapter Cable Connectors, Network End
V.35 Connections
The V.35 interface is recommended for speeds up to 48 kbps, although it is often used successfully at
4 Mbps.
The network end of the V.35 adapter cable provides a standard 34-pin Winchester-type connector. (See
Figure 2-3
.) V.35 cables are available with a standard V.35 plug or receptacle in either DTE or DCE
mode.
Figure 2-3
V.35 Adapter Cable Connectors, Network End
X.21 Connections
The X.21 interface uses a 15-pin connection for balanced circuits and is commonly used in the United
Kingdom to connect public data networks. X.21 relocates some of the logic functions to the DTE and
DCE interfaces and, as a result, requires fewer circuits and a smaller connector than EIA/TIA-232.
The network end of the X.21 adapter cable is a standard DB-15 connector. (See
Figure 2-4
.) X.21 cables
are available as either DTE (DB-15 plug) or DCE (DB-15 receptacle).
H1344a
DTE
DCE
H1616a
DTE
DCE
