Installation manual

Version 6.0 21 February 2010
Installation Manual 2. Installing the Device
¾ To connect the BRI ports:
1. Connect the BRI cable to the device's BRI RJ-45 port.
2. Connect the other end of the cable to your ISDN telephone or PBX/PSTN switch.
A BRI port can be configured either as TE (Termination Equipment/user side) or NT
(Network Termination/network side). The connector pinouts vary according to the
configuration, as detailed in the following figure:
Figure 2-9: RJ-45 Connector Pinouts for BRI Ports
When configured as NT, the BRI port drives a nominal voltage of 38 V with limited current
supply of up to 100 mA. The voltage is of Power Source 1 type (line voltage).
2.4.6 Connecting BRI Interfaces for PSTN Fallback
The PSTN Fallback feature provides a BRI interface connection to the PSTN upon a power
outage (i.e., Ethernet link failure). This allows a telephone or PBX connected to a BRI port
to continue making calls through the PSTN network (instead of through the IP network).
The PSTN Fallback is provided by connecting adjacent BRI ports, where one port is
connected to, for example, a PBX and its adjacent port is connected to an active PSTN line
(i.e., normal operation, not only dedicated to Fallback). In the event of a power failure, a
relay connects the adjacent BRI ports (i.e., ports I to II, and ports III to IIII) by the closing of
a metallic switch inside the module.
Figure 2-10: PSTN Fallback for BRI Ports