3Com 3C13755-US - Router 5642 Installation Manual page 29

A network port connector is available for extending the E1 cable. See Figure 27.
Both ends of the connector are RJ-45 jacks that can be used to connect two
120-ohm balanced twisted pair cables. In addition, a 75-ohm to 120-ohm adapter
is available.
Figure 27 Extended Connection of E1 120-Ohm Balanced Twisted Pair Cable
DB-15
Router
Network interface connector
120-ohm balanced twisted pair
To connect the cable:
1 Power off the router.
2 Check the type of E1 cable and correctly set the DIP switch (the default setting of
the E1 interface impedance is 75-ohm).
3 Connect the DB-15 connector of the E1 cable to the 1-Port Fractional E1 SIC
interface card.
4 Connect the other end of the E1 cable to the corresponding network device.
If you do not need to extend the E1 cable, directly connect the RJ-45
connector of the 120-ohm balanced twisted pair cable to the RJ-45 interface of
the remote equipment.
If you need to extend the E1 cable, connect the RJ-45 connector of the
120-ohm balanced twisted pair cable to the network connector and the other
end of the network connector to the network equipment via 120-ohm E1
trunk cable. See Figure 27.
The wire marked TX in the E1 cable should be connected with the peer wire
marked RX and the wire marked RX should be connected with the peer wire
marked TX.
The E1 cable, coaxial connector, network port connector, and 75ohm-to-120ohm
adapter are optional and must be ordered with the 1-Port Fractional E1 SIC.
When you have connected the cables:
1 Power on the router, and check the SLOT1 or SLOT2 LED on the front panel of the
router. If the LED is green, the interface card has passed the POST and can operate
normally. If the LED is off, POST failed and you should contact your Service
representative.
2 Check the status of the synchronous (LINK) LED on the 1-Port Fractional E1 SIC
panel. If the LED is off, the line is faulty and the signals are not synchronous.
Check the line.
RJ-45
RJ-45
120-ohm E1 trunk cable
1-Port Fractional E1 SIC
Network
devices,
such as
leased line
27