# Connecting to the telephone network

This topic provides instructions for connecting to the telephone network.

Warning: | Important safety notes for telephony connections Allow only qualified technical personnel to install this board and associated telephone wiring. Make sure the PC chassis is grounded through the power cord or by other means before connecting the telephone line. Never install telephone wiring during a lightning storm. Never install telephone jacks in wet locations. Telephone companies provide primary lightning protection for their telephone lines. However, if a site connects to private lines that leave the building, make sure that external protection is provided.

As shown in the following illustration, the end bracket on the AG 2000C rear I/O transition board has an RJ-21 connector. The connector has 25-pair interfaces:

RJ-21 connector

The connector is designed to accommodate a 25-pair cable. As shown in the following illustration, this cable is commonly wired to a punch-down block or breakout box.

Connecting the board

The RJ-21 connector on the cable must be the 180-degree design. The common 90-degree RJ-21 connector is not compatible with the AG 2000C board.

90-degree versus 180-degree RJ-21 connector

The following illustration shows the pin locations for the RJ-21 connector on an AG 2000C rear I/O transition board:

Connector pinout

The following table describes the pinouts for the RJ-21 connector:

Trunk | Ring pin | Tip pin |  | Trunk | Ring pin | Tip pin
--- | --- | --- | --- | --- | --- | ---
1 | 1 | 26 |  | 13 | 13 | 38
2 | 2 | 27 |  | 14 | 14 | 39
3 | 3 | 28 |  | 15 | 15 | 40
4 | 4 | 29 |  | 16 | 16 | 41
5 | 5 | 30 |  | 17 | 17 | 42
6 | 6 | 31 |  | 18 | 18 | 43
7 | 7 | 32 |  | 19 | 19 | 44
8 | 8 | 33 |  | 20 | 20 | 45
9 | 9 | 34 |  | 21 | 21 | 46
10 | 10 | 35 |  | 22 | 22 | 47
11 | 11 | 36 |  | 23 | 23 | 48
12 | 12 | 37 |  | 24 | 24 | 49

Note: Pins 25 and 50 are not used.

## Ferrite block

The AG 2000C board is shipped with a ferrite block (P/N 33210). Attach the ferrite block to the RJ-21 cable with one loop as shown in the following illustration. The AG 2000C board passes FCC Part 15, Class A without this ferrite block.

Ferrite block

## Developer's cable kit

To help you get started, NMS provides an optional developer's cable kit (P/N 80659). The kit contains two 10-foot RJ-21 cables and two breakout boxes. Each breakout box connects one RJ-21 to 24 standard RJ-11 (POTS) jacks for individual phones. You can use the cables to connect to the breakout boxes or to standard 66 or 110 blocks.

All components of the developer's cable kit sold by NMS are also commercially available from telephone product distributors such as Graybar and Anixter. These distributors can provide variations in cable lengths.