Nortel Networks BCM50 manual RJ-21 telephony connector, Analog telephones

52 Chapter 2 Introducing the BCM50 hardware

The cooling fan mounts in the back of the BCM50 enclosure.

For information about how to install or replace the cooling fan, refer to “Replacing an internal component” on page 189.

RJ-21 telephony connector

Use the RJ-21 telephony connector to connect a 25-pair (RJ-21) cable to the main unit. These 25 pairs of wires are then connected to the following telephony devices (see “RJ-21 telephony connector wiring chart” on page 205):

•4 analog lines

Use these connections for analog trunks from the Public Switched Telephone Network (PSTN).

•4 analog telephones

Use these connections for analog telephony devices such as single line telephones, fax machines, and modems.

•Auxiliary ringer

Use this connection for an auxiliary ringer (customer supplied). The BCM50 system uses the auxiliary ringer to control the cadence of an auxiliary ringer. You must use this output in a low current, low voltage application only. Do not use this output for switching the auxiliary ringer directly.

•Page output

Use this connection to connect an internally generated voice paging signal to an external paging amplifier (customer supplied).

•Page relay

When you use the page output to connect an external paging amplifier, you also use the page relay. The page relay connects to a floating relay contact pair. The BCM50 system uses the page relay to control the external paging amplifier.

•Music input

Use the Music input to connect an external music source that supplies a signal to held lines (music on hold) or telephone speakers (background music). The input source can be any available radio or music source approved for connection to the network. If you use this connection, do not use the Music input jack on the main unit faceplate.

•12 digital telephones

Use these connections for digital telephones. For a list of digital telephones that are compatible with the BCM50 system, refer to “Telephones and adapters” on page 54.

Warning: External equipment connected to the auxiliary ringer, page relay, page output, and music-on-hold interfaces must use safety extra low voltage (SELV).

All four interfaces are SELV and the external equipment connected to these interfaces must be SELV. If these interfaces are not SELV, you must use external line isolation units (LIU).

N0027152 01