3Com 3C13701 Installation Manual page 39

Connecting E1 Interface Cable
CAUTION:
Examine the interface mark before connection to avoid cable mis-insertion and router
■
damage.
When the E1 interface cable is routed outdoors, you need use the special lightning
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protection unit at the input end to prevent possible damage.
1 Check the E1 cable type and choose correct impedance value of the E1 interface through
the inverter switch.
2 Insert the DB15 connector into the E1 interface of the router.
3 Connect the other end to the right network devices.
For 75Ω unbalanced coax cable
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Connect the cable in this way:
If you choose only a single BNC connector, just connect the BNC connector to the peer
device.
If you choose two BNC connectors (for extending E1 interface cables), connect the BNC
connector of the 75Ω unbalanced coax cable to a coax connector assembly, which is
connected to a 75Ω E1 trunk cable. The 75Ω E1 trunk cable is then connected to the
peer device.
CAUTION: Connect the Tx end of the E1 interface cable to the Rx end of the peer unit,
and Rx end of the E1 interface cable to the Tx end of the peer unit.
Figure 32 Extending two E1 75Ω unbalanced coax cables
If the peer device provides the 120Ω interface, you need to use 75Ω−120Ω converter or
120Ω cable.
For 120Ω balanced twisted pair cable
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Connect the cable in this way:
If you choose only a single RJ45 connector, just connect the RJ45 connector to the peer
device.
Connecting Router to the WAN 39