3Com MSR 30, MSR 20 Balanced twisted pair cables, SIC-1VE1. By default, they are not supplied

48CHAPTER 2: SMART INTERFACE CARDS

	A network interface connector is available for extending the E1 cable. Both ends
n 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.
	For the pinouts of E1 cables, see Low-End and Mid-Range Series Routers Cable
	Manual.
c	CAUTION: E1 cable, coaxial connector, network interface connector and
	75ohm-to-120ohm adapter are optional. Please order them together with

SIC-1VE1. By default, they are not supplied.

Connecting the Interface

Cable

c CAUTION: When using E1 cable outdoors, you are recommended to install a special lightning arrester on the input end of the cable in order to avoid lightning more effectively.

If the SIC has been properly installed, follow these steps to connect the cable:

Step 1: Check the type of E1 cable and correctly set the DIP switch (the ex-factory setting of the interface impedance is 75-ohm);

Step 2: Connect the DB-15 connector of E1 cable to SIC-1VE1;

Step 3: Connect the other end of the E1 cable to the corresponding network device:

1When the E1 cable is a 75-ohm unbalanced coaxial cable:

■Directly connect the BNC connector of the cable to the remote equipment if there is no need for extension, or

■Connect the BNC connector of the cable to the coaxial connector and the other end of the coaxial connector to the remote network equipment through a 75-ohm E1 trunk cable, if cable extension is needed.

CAUTION: The wire marked TX in the E1 cable should be connected to the peer
c wire marked RX and the wire marked RX should be connected to the peer wire
marked TX.
Figure 43 Extending an E1 75-ohm non-balanced 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