Cisco WS-X4013 Hardware Maintenance Manual - Page 64

Making Network Connections Caution For proper router operation, both ends of the 50-pin dual serial EIA/TIA-232 serial DCE cable, and any cable attached to it, must be connected. If this cable must be detached, detach the router end first. If the end away from the router is disconnected, the line connection will "flap." The interrupts generated from such a condition could cause the router to shut down. When all your network connections are complete, proceed to the section later in this chapter, "Making Final Connections to the Router." Making BRI Connections Using the appropriate cable (see the following section, "BRI Cable Specifications"), connect the Basic Rate Interface (BRI) port to the Integrated Services Digital Network (ISDN) through the NT1. The common carrier will provide the NT1 connection worldwide, except in North America, where the NT1 is customer owned. The NT1 is an ISDN channel service unit/digital service unit (CSU/DSU). Warning Network hazardous voltages are accessible in the BRI cable. If you detach the BRI cable, detach the end away from the router first to avoid possible electric shock. Network hazardous voltages are also accessible on the network processor module in the area of the BRI port (RJ-45 connector) even when power is turned OFF. (See Figure 3-7 and Figure 3-8.) The BRI network processor module supports point-to-point operation at OSI Layer 1. Only one source (the transmitter) and one sink (the receiver) are actively transmitting at any time in each direction at an S interface (CCITT specification I.430 section 3.1). The BRI module does not support a point-to-multipoint wiring configuration. Because the BRI module does not support point-to-multipoint configuration, D-channel access procedures are not implemented. BRI Cable Specifications The specifications for the BRI cable are given in Table 3-1. Table 3-1 BRI Cable Specifications Parameter Resistance (@ 96 kHz1) Capacitance (@ 1 kHz) High-Capacitance Cable 160 ohms/km 120 nF/km2 Low-Capacitance Cable 160 ohms/km 30 nF/km Impedance (@ 96 kHz) 75 ohms 150 ohms Wire diameter 0.024" (0.6 mm) 0.024" (0.6 mm) Distance limitation 32.8' (10 m) 32.8' (10 m) 1. kHz = kilohertz. 2. nF = nanoFarad. The BRI network processor module (see Figure 3-7 and Figure 3-8) supports eight BRI ports. Each BRI port is an RJ-45 8-pin connector. Use an appropriate cable to connect the BRI module directly to an Integrated Services Digital Network (ISDN) through an ISDN channel service unit/digital service unit (CSU/DSU) called the NT1. The common carrier will provide the NT1 connection, except in North America, where the NT1 is customer owned. 3-6 Cisco 4000 Series Hardware Installation and Maintenance