ShoreTel analog connections and the 66 Block!

It is surprising that in the 21st century we are still punching down copper lines! None the less fax machines, credit card devices, postage machines and security circuits still populate the installed base of telephone systems. If you are converting from a legacy phone system to a VoIP solution, on premise or hosted, you will have to plan for “analog” devices. A “best practice” for any VoIP phone system is to have at least one analog telephone company provided central office line, per site, attached for power failure and E911 operation. ShoreTel, for example, has conveniently made it possible for one “port” on a ShoreGear switch to cut through to another port enabling basic POTS operation during a commercial power failure.

The venerable 66 type punch down block is typically used to accomplish analog device connectivity. We like to think of the 66 block as the “border controller” in the analog world. You can easily separate the telephone company (read WAN) from the customer owned and operated equipment (read LAN) by removing the bridging clip that separates one side of the block from the other. VoIP or not, the 66 block is not going away. Phone technicians love 66 blocks, but IT technicians prefer “patch panels”? Unfortunately, the telephone company typically delivers the circuits at the MPOE or “main point of entry” downstairs in the basement! If you want to get it up to your patch panel, you are going to have to deal with the 66 block.

The basic components are the 66M1-50 split 25 pair block and wall mount bracket. The block is designed to cut down two 25 pair cables on each side of the block using an industry standard color code. Typically you would put your equipment on one side of the block and your station distribution on the other side of the block. Generally “cross connect” pairs act as the equivalent of patch cables, interconnecting equipment and devices. A “bridge” clip is used to connect one side of the block to the other side. If you are thinking ahead, you might use a “rat tail” cable that ends in a male or female amphenol connector to limit punch down and facilitate quick connect.

The ShoreGear switches have a male RJ-21X amphenol connector on the face plate. You will need a female or red amphenol connector to bring 25 pairs of copper out to your 66 block or patch panel. Optionally, 66 blocks can be obtained with an RJ-21X amphenol connector built in. For reasons nobody can explain, the Male connector has a Blue cap and the Female connector has a Red cap over the connector pins for protection. Beware of what sex your connector needs to be!

There is an industry agreed color code and sequence that defines how a 25 pair cable should be punched down. ShoreGear switches, however do not use all pairs. Each switch type has a different port pin out, so pay attention to your planning and installation guide. Additionally, not all analog ports are equal on a ShoreTel switch. There are three types: Universal, Fxo and Fxs so make sure you know what device you are needing to connect and use the correct port type. Universal ports will support either a Central Office line (Fxo) or a Station device (Fxs).

The video walks you through the details of connecting a ShoreGear switch to a 66 block, outlines various cable alternatives and details the color code! With the help of our friends at cable there is a detailed presentation on how to “punch down” a 25 pair cable on a 66 block. Enjoy and as always comments are welcome!