3Com MSR 30, MSR 20, MSR 50 manual End

168CHAPTER 4: FLEXIBLE INTERFACE CARDS

Connecting the Interface

Cable

c CAUTION: Before you connect a port, read its label carefully; a wrong connection can cause damages to the interface card and even the device.

If outdoor cabling is involved, consider to install a special lightning arrester at the input end of the interface cable for better lightning protection.

Connecting the interface cable of the FIC-1E1/FIC-2E1/FIC-1E1-F/FIC-2E1-F

Step 1: Identify type of the E1 cable, and set the DIP switch for the to-be-connected E1/FE1 port correctly.

Step 2: Plug the DB-15 connector of the E1 cable into the E1/FE1 port on the card.

Step 3: Connect the other end of the E1 cable to another device.

When using a 75-ohm unbalanced coaxial cable, do the following:

■If no cable extension is needed, directly connect the BNC connector of the cable to the device.

■If cable extension is needed, connect the BNC connector of the cable to a coaxial connector, and then connect the other end of the coaxial connector to the device using a 75-ohm E1 trunk cable.

CAUTION: When connecting the router to another device using an E1 coaxial
c cable, make connection with the TX end to the RX end and the RX end to the TX
end.
Figure 205 Extending an E1 75-ohm unbalanced coaxial cable
		DB-15			BNC	Network
				BNC
	Router					devices
						such as DDN
			Coaxial connector 75-ohm E1 trunk cable
75-ohm non-balanced coaxial cable

■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.

When using a 120-ohm balanced twisted-pair cable, do the following:

■If no cable extension is needed, directly connect the RJ-45 connector of the cable to the RJ-45 port on the device.

■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.