5-5
Cisco 1800 Series Routers (Modular) Hardware Installation Guide
OL-5876-03
Chapter 5 Cable Information and Specifications for Cisco 1800 Series Routers (Modular)
Preparing to Connect to a Network
ISDN BRI Connections
The BRI WICs provide ISDN and BRI connections. BRI WICs are available with either an S/T interface
that requires an external Network Termination 1 (NT1), or a U interface that has a built-in NT1. You can
install the BRI WICs in any available WIC slots in the chassis.
Warning
The ISDN connection is regarded as a source of voltage that should be inaccessible to user contact.
Do not attempt to tamper with or open any public telephone operator (PTO)-provided equipment or
connection hardware. Any hardwired connection (other than by a nonremovable,
connect-one-time-only plug) must be made only by PTO staff or suitably trained engineers.
Statement 23
Warning
Hazardous network voltages are present in WAN ports regardless of whether power to the unit is OFF
or ON. To avoid electric shock, use caution when working near WAN ports. When detaching cables,
detach the end away from the unit first.
Statement 1026
Use a BRI cable (not included) to connect the BRI WIC directly to an ISDN.
Table 5-3
lists the
specifications for ISDN BRI cables. For information about pinouts, see
Cisco Modular Access Router
Cable Specifications
.
For more information on BRI WICs, see
Installing Cisco Interface Cards in Cisco Access Routers
.
CSU/DSU Connections
CSU/DSU WICs are available that provide switched 56-kbps connections, or full or fractionalized T1
connections.
For more information on CSU/DSU WICs, see
Installing Cisco Interface Cards in Cisco Access Routers
.
Table 5-3
ISDN BRI Cable Specifications
Specification
High-Capacitance Cable
Low-Capacitance Cable
Resistance (at 96 kHz)
160 ohms/km
160 ohms/km
Capacitance (at 1 kHz)
120 nF
1
/km
1.
nF = nanofarad.
30 nF/km
Impedance (at 96 kHz)
75 ohms
150 ohms
Wire diameter
0.024 in. (0.6 mm)
0.024 in. (0.6 mm)
Distance limitation
32.8 ft (10 m)
32.8 ft (10 m)
