3Com Router 5000 Family
Installation Guide
Chapter 4 Installation of the Router
3Com Corporation
4-22
Matching cable
E1 75
Ω
unbalanced coax cable
E1 120
Ω
balanced coax cable
Coax connector, network interface connector, 75
Ω−
120
Ω
converter (with BNC connector)
Operating
mode
E1, CE1, ISDN PRI
Function
Backup
Terminal access
ISDN PRI
2) E1 interface cable
E1 interface cable, which is G.703-compatible, may be 75
Ω
unbalanced coax cable or
120
Ω
balanced twisted pair cable.
z
75
Ω
unbalanced coax cable
The cable is attached with DB15 (male) connector for the router end, and with BNC
connector for the network end. See the following figure.
Figure 4-31
E1 75
Ω
unbalanced coax cable
Note:
You can also choose to attach both ends with BNC connectors, for extending two 75
unbalanced coax cables.
z
120
Ω
balanced twisted pair cable
The cable is attached with DB15 (male) connector for the router end, and with RJ45
connector for the network end. See the following figure.