Cisco Systems 1900 Series ユーザーズマニュアル

Synchronous interface—Maximum baud rate is 128 kbps, full-duplex.

The BRI WICs provide Integrated Services Digital Network (ISDN) Basic Rate Interface (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.

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

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. 

 lists the 

specifications for ISDN BRI cables. For information about pinouts, refer to the 

 online document, which is located on Cisco.com.

For more information on BRI WICs, refer to Cisco.com.

CSU/DSU WICs are available that provide switched 56-kbps connections, or full or fractionalized T1 
connections.

For more information on CSU/DSU WICs, refer to Cisco.com.

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)