Inside Wiring

Inside Wiring: That telephone wiring located inside your premises or building. Inside Wiring starts at the telephone company's Demarcation Point and extends to the individual phone extensions. Traditionally, Inside Wiring was installed and owned by the telephone company but now you can install your own wiring. And most companies installing new phone systems are installing their own new wiring because of potential problems with reusing the old telephone company cable.

Inside Wire or Line Backer: names of products sold by LECs (Local Exchange Carriers) to their customers as "insurance" on their inside wire. Customers pay upwards of $5 per month in order not to have to pay the phone company a pile of cash if something goes wrong with their inside wiring.

66 Block

The most common type of connecting block used to terminate and cross-connect twisted-pair cables. It was invented by Western Electric eons ago and has stood the test of time. It is still being installed. Its main claims to fame: Simplicity, speed, economy and space. You don't need to strip your cable of its plastic insulation covering. You simply lay each single conductor down inside the 66 block's two metal teeth and punch the conductor down with a special tool, called a punch-down tool. As you punch it down, the cable descends between the two metal teeth, which remove its plastic insulation (it's called insulation displacement) and the cable is cut. The installation is then neat and secure. 66 blocks are typically rated Category 3 and as such as used mostly for voice applications, although Category 5 66 blocks are available. 66 blocks are open plastic troughs with four pins across, and the conductors are more susceptible to being snagged or pulled than conductors terminated on other types of blocks (e.g., 110, Krone or BIX).

A note on the Bell Labs numbering system… They just started with "number 1" on whatever system they were working on. TD1 radio, TD2 radio, etc., Whenever there was a "hole" in the sequence, that meant that the labs had worked on something, but it didn't pan out for some reason.

Drop (and variants of Drop)

Drop:
1. A wire or cable from a pole or cable terminal to a building.
2. That portion of a device that looks toward the internal station facilities, e.g., toward an AUTOVON 4-wire switch, toward a switchboard, or toward a switching center.
3. Single channel attachment to the horizontal wiring grid (wall plate, coupling, MOD-MOD adapter).
4. The CO (central office) side of test jacks.
5. To delete, intentionally or unintentionally, part of a signal for some reason, e.g., dropping bits.

Drop Cable:
1. The outside wire pair which connects your house or office to the transmission line coming from the phone company's CO.
2. In local area networks, a cable that connects a network device such as a computer to a physical medium such as an Ethernet network. Drop cable is also called transceiver cable because it runs from a network node to a transceiver (a transmit/receiver) attached to the trunk cable.

Drop Loop: The segment of wire from the nearest telephone pole to your home or business.

Drop Wire: Wires going from your phone company to the 66 Block (type of punchdown block used to connect sets of wires in a telephone system) or protector in your building.

Distribution Cable (OSP and ISP)

Distribution Cable, OSP (Outside Plant): The cable running from a central office or remote terminal to the side of a subscriber's lot.

Distribution Cable, ISP (Inside Plant): Cables usually running horizontally from a closet on a given floor within a building. Distribution cables may be under carpet, simplex, duplex, quad, or higher fiber count cables.

Feeder Cable

A group of wires, usually 25-pair or multiples of 25-pair, that supports multiple phones in a single cable sheath. These cables may or may not be terminated with a connector on one or both ends. A Feeder cable typically connects an intermediate distribution frame (IDF) to a main distribution frame (MDF). But the term "feeder cable" is also used in backbone wiring.

For a basic illustration, you can access the following link:

http://www.svrops.com/svrops/Images/HorizCC.gif


Bellcore defines the term slightly differently: A large pair-size loop cable emanating from a central office and usually placed in an underground conduit system with access available at periodically placed manholes. (This is a very common usage for the term.)


Feeder Route: A network of loop cable extending from a wire center into a segment of the area served by the wire center.

Serving Area Interface (SAI)

A serving area interface is part of a phone company's outside plant. It is a fancy name for a box on a pole, a box attached to a wall or a box in the ground that connects the phone company's feeder or subfeeder cables (those coming from the central office) to the drop wires or buried service wires that connect to the customer's premises. It's also called a cross-wire box.

(See below for picture of a typical grounded Serving Area Interface)




Source: http://upload.wikimedia.org/wikipedia/en/thumb/9/9d/1200_pair_SAI.jpg/180px-1200_pair_SAI.jpg

Tandem Switch

Tandem: In a telecommunications context, the term refers to switches, circuits, or other Network Elements (NEs) that serve to allow other NEs to work together. For example, tandem switches, or tandem offices, serve to interconnect other, lesser switches, (i.e. Central Offices [CO's] or lesser tandems). Tandem switches, in the purest sense of the term, serve no end users directly, as that is the responsibility of the COs. Rather, they strictly serve to interconnect the COs, which are at the lowest level of the switching hierarchy in the PSTN. Tandem tie trunks serve to interconnect tandem switches.


Tandem Switch: Tandem is a telephony term meaning to "connect in series." Thus a tandem switch connects one trunk to another. A tandem switch is an intermediate switch or connection between an originating telephone call location and the final destination of the call. The tandem point passes the call along. A PBX can often handle tandem calls from other/to other locations as well as process calls to, from and within its own location.



Source: http://img.zdnet.com/techDirectory/CO1.GIF