3Com MSR 20, MSR 30, MSR 50 manual Connecting the Interface Cable

FIC-2BSV/FIC-4BSV Module 223

Interface Cable When a BSV interface works in user mode, it uses a straight-through ISDN S/T interface cable for connection. At the two ends of the cable are RJ-45 connectors with pins 3 and 6 for data transmission and pins 4 and 5 for data receiving.

Figure 274 Straight-through ISDN S/T cable

Yellow	Green
Green	Yellow
RedBlack	Black
	Red

When a BSV interface works in network mode, it uses a crossover ISDN S/T interface cable for connection, with pins 3 and 6 for data transmission and pins 4 and 5 for data receiving. At one end of the cable is an RJ-45 male connector for connecting the FIC-2BSV/FIC-4BSV interface and at the other end of the cable is an RJ-45 female connector for connecting a TE device.

Figure 275 Crossover ISDN S/T cable

Connecting the Interface

Cable

c CAUTION:

■If outdoor cabling is involved, you need to install a lightning arrester at the input end of the ISDN BRI S/T interface cable to avoid lightning strike.

■When connecting the interface cable, pay attention to the mark on the interface to avoid wrong insertion, which may damage the interface card or even the router host.

Step 1: Identify the operating mode of the BSV interface. If the interface is to be connected to an ISDN network, it should operate in user mode; if the interface is to be connected to a TE device, such as a digital phone or another BSV interface in user mode, the interface should operate in network mode.