Connecting rj-21 cables, Onnecting, Rj-21 – NetComm NCT240 User Manual
Page 17: Ables
NetComm NCT240 Installation Guide Release 1.0
Connecting RJ-21 Cables
For incoming phone lines, a splitter can connect directly to a PBX or can be connected via a
punch-down block. The particular connection method used will depend on the type of
connectors and cables supported on the PBX, and on the existing cabling in the building.
The EE lines from the splitter interface of NCT240 are connected to the punch-down block that
connects the phone lines that run up to the end users. If the NCT240 is installed in a rack, it may
be convenient to use a patch panel between the splitter interface and the punch-down block.
For all connections to the splitter interface, cables with standard Telco RJ-21 connectors must
be used. Some punch-down blocks can be pre-wired with an RJ-21 connector provided, making
the connection simple. Otherwise, a cable with an RJ-21 on one end and free wiring on the other
end will be required.
Figure 4-6. Connecting to the Punch-down Blocks
Follow the steps below to connect an EE Splitter to a building’s phone-line system using a
1. Connect one RJ-21 flat cable from the PBX to the connector on the splitter’s rear panel
Note: Some installations may also have a separate punch-down block between the PBX and the
EE Splitter. In this case, connect an RJ-21 cable from the splitter’s “PBX/MDF” connector
to the punch-down block.
2. Connect another RJ-21 flat cable from the RJ-21 connector on the front of the splitter labeled
“Line” to the building’s phone-line punch-down block. Note that the connection to the
punch-down block usually requires punching down the free wires from the RJ-21 cable.
Note: If you use pre-wired punch-down blocks with RJ-21 connectors, be sure they are wired to
match the pin assignments of ports on the back of the splitter. To ensure that your cables
are properly wired, refer to “RJ-21 Port Pin Assignments” on page B-6.