Chapter 9 Connecting the cables to the BCM50 system 105
BCM50 Installation and Maintenance Guide
8 Connect the 12 pairs of wires for the digital telephones to the local connecting blocks.
9 Select the appropriate option for your system:
• If your BCM50 system has an expansion unit, proceed to “Connecting telephone lines to
the expansion units” or “Connecting extensions to the expansion units” on page 106.
• If your BCM50 system does not have an expansion unit, proceed to “Connecting the
auxiliary equipment” on page 107.
Refer to the “RJ-21 telephony connector wiring chart” on page 205 for detailed information about
wiring the RJ-21 telephony connector.
Connecting telephone lines to the expansion units
Telephone lines connect to the expansion unit through the connectors on the MBM installed in the
expansion unit.
To connect telephone lines to DTM, BRIM, or 4x16 MBMs
1 Read the warnings in “Wiring warnings” on page 103.
2 Obtain a telephone cable that has a modular plug that matches the MBM to which you are
connecting:
• RJ-48C — for DTM
• RJ-45 — for BRIM
• RJ-11 — for 4x16
3 Plug the modular cable into the jack in the front of the MBM.
4 Connect the other end of the cable to the telephone company demarcation blocks of the
building.
5 If you are connecting telephone lines to a 4x16 or BRIM, repeat steps 2 to 4 for each line you
are connecting.
6 Select the appropriate option for your system:
• If you are connecting a 4x16 MBM, go to “Connecting extensions to the expansion units”
on page 106 for instruction about wiring the extensions for this MBM.
Warning: If the network ISDN is a U-loop, the BRIM must be connected only to an
NT1 provided by the service provider. The NT1 must provide a Telecommunication
Network Voltage (TNV) to Safety Extra Low Voltage (SELV) barrier.
Note: Do not attempt to plug digital equipment into the auxiliary (AUX) jacks on the
front of 4x16 MBM.
