3Com 3C13886 - Router OC-3 ATM SML Flexible Interface Card Installation Manual page 131

3Com Router Module Guide
Note:
To extend an E1 75-ohm unbalanced coaxial cable, you can select a pair of coaxial connectors with a
BNC receptacle at each end to connect the BNC receptacles of the cable each to a 75-ohm unbalanced
coaxial cable with BNC connectors.
120-ohm balanced twisted-pair cable
As shown in the following figure, at the router end of the cable is a DB-15 plug and at
the network end is an RJ-45 connector.
Figure 4-22 E1 120-ohm balanced twisted-pair cable
Note:
To extend an E1 120-ohm balanced twisted-pair cable, you can select a network connector with an
RJ-45 receptacle at each end to connect the cable to another 120-ohm balanced twisted-pair cable.
In addition, you are available with 75-ohm-to-120-ohm adapters.
Note:
E1 cable, coaxial connector, network connector, and 75-ohm-to-120-ohm adapter are all optional
accessories. They are provided only when ordered.
II. Interface cable of the ROUTER 4-PORT CE1/PRI FIC
ROUTER 4-PORT CE1/PRI FIC provides two types of 1-to-4 adapter cables: 120-ohm
4E1 and 75-ohm 4E1. At one end of both cables is a DB-25 connector for connecting
the router, and at the other end are four DB-15 connectors for connecting E1 cables.
You can distinguish between them by the main label text: "4E1-120Ohm-CAB" for the
120-ohm 4E1 adapter cable and "4E1-75Ohm-CAB" for the 75-ohm 4E1 adapter
cable.
4-22
Chapter 4