Chapter 9 Connecting the cables to the BCM50 system 111Installation and Maintenance Guide9 Select the appropriate option for your system:• If your BCM50 system has an expansion unit, proceed to Connecting telephone lines tothe expansion units on page 111 or Connecting extensions to the expansion units on page112.• If your BCM50 system has no expansion unit, proceed to Connecting the auxiliaryequipment on page 113.For detailed information about wiring the RJ-21 telephony connector, see RJ-21 telephonyconnector wiring chart on page 207.Connecting telephone lines to the expansion unitsTelephone lines connect to the expansion unit through the connectors on the MBM installed in theexpansion unit.To connect telephone lines to DTM, BRIM, or 4x16 MBMs1 Read the warnings in Wiring warnings on page 109.2 Obtain a telephone cable that has a modular plug that matches the MBM to which you areconnecting:• RJ-48C—for DTM• RJ-45—for BRIM• RJ-11—for 4x163 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 thebuilding.5 If you connect telephone lines to a 4x16 or BRIM, repeat steps 2 to 4 for each line.6 Select the appropriate option for your system:• If you connect a 4x16 MBM, go to Connecting extensions to the expansion units on page112 for instruction about wiring the extensions for this MBM.• If your BCM50 system has another expansion unit, repeat this procedure if you add moretelephone lines, or proceed to Connecting extensions to the expansion units on page 112 ifyou add extensions.Warning: If the network ISDN is a U-loop, you must connect the BRIM only to anNT1 provided by the service provider. The NT1 must provide a TelecommunicationNetwork Voltage (TNV) to Safety Extra Low Voltage (SELV) barrier.Note: Do not attempt to plug digital equipment into the auxiliary (AUX) jacks on thefront of 4x16 MBM.
