3Com 3C13886 Installation Guide - Page 134

3Com Router Module Guide Chapter 4 Caution: When connecting the router to another device using an E1 coaxial cable, make connection with the TX end to the RX end and the RX end to the TX end. DB-15 Router BNC BNC Network devices such as DDN Coaxial connector 75-ohm E1 trunk cable 75-ohm non-balanced coaxial cable Figure 4-25 Extending an E1 75-ohm unbalanced coaxial cable z If the to-be-connected network device has a 120-ohm port, you need a 75-ohm-to-120-ohm adapter or a 120-ohm cable instead. 2) When using a 120-ohm balanced twisted-pair cable, do the following: z If no cable extension is needed, directly connect the RJ-45 connector of the cable to the RJ-45 port on the device. z If cable extension is needed, connect the RJ-45 connector of the cable to a network interface connector, and the other end of the network interface connector to the device using a 120-ohm E1 trunk cable. DB-15 Router RJ-45 RJ-45 Network devices such as DDN Network interface connector 120-ohm balanced twisted pair 120-ohm E1 trunk cable Figure 4-26 Extending an E1 120-ohm balanced twisted-pair cable Step 4: Power on the router, and check the behavior of the LINK LED on the card: OFF means fault occurs on the line and the signal is not synchronized. Check the line status. 4-25