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
Warning
Use a BRI cable (not included) to connect the BRI WAN interface card directly to an ISDN. The following
table lists the specifications for ISDN BRI cables.
Table 21: ISDN BRI Cable Specifications
Low-Capacitance Cable
High-Capacitance Cable
Specification
160 ohm/km
160 ohm/km
Resistance (at 96 kHz)
30 nF/km
120 nF/km
nF= nano
Farad
Note
Capacitance (at 1 kHz)
150 ohm
75 ohm
Impedance (at 96 kHz)
0.024 in. (0.6 mm)
0.024 in. (0.6 mm)
Wire diameter
32.8 ft (10 m)
32.8 ft (10 m)
Distance limitation
ISDN BRI Pinouts
To prevent damage to the system, ensure that you connect the BRI cable only to the BRI connector and
not any other RJ-45 connector. Also, make certain that you connect the E&M cable to an E&M connector
only.
Caution
The following table lists the connector signals and pinouts for an ISDN BRI S/T port.
Table 22: ISDN BRI S/T Port Signals and Pinouts (RJ-45)
Polarity
NT
3
TE
2
8-Pin
1
+
RX
TX
3
+
TX
RX
4
–
TX
RX
5
–
RX
TX
6
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Cable Specifications and Information
ISDN BRI Pinouts