Cisco WS-X45-SUP6-E Hardware Maintenance Manual - Page 52

Network Connection Considerations The specifications for the BRI cable are given in Table 2-6. Table 2-6 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. Note The multiport BRI network processor module requires that all its interfaces connect to the same carrier or from carriers with synchronized master clocks. If the BRI module connects to ISDN interfaces which have an unsynchronized master clock, the module's interfaces will occasionally lose some packets. Channelized T1 Connections The Cisco 4000 series router supports a channelized T1 (CT1) network processor module with one T1 interface.The CT1 provides one channelized T1 connection via a serial cable to a channel service unit (CSU). On the CT1, the controller provides up to 24 virtual channels. Each virtual channel is presented to the system as a serial interface that can be configured individually. This interface is the physical media that supports ISDN PRI. The CT1, shown in Figure 2-32, provides a controller for transmitting and receiving data bidirectionally at the T1 rate of 1.544 Mbps. For wide-area networking, the CT1 can function as a concentrator for a remote site. 2-30 Cisco 4000 Series Hardware Installation and Maintenance