Load Coil

Load coils are also known as impedance matching transformers. Load coils are used by the telephone companies on long analog POTS (Plain Old Telephone Service) lines to filter out frequencies above 4 kHz, using the energy of the higher frequency elements of the signal to improve the quality of the lower frequencies in the 4 kHz voice range. Load coils are great for analog voice grade local loops, but must be removed for digital circuits to function. Load coils must be removed for DSL loops, as the frequencies required are well above 4 kHz. Today many phone companies offer broadband service, but often tell their customers that they can't get the service because "you live too far from the telephone company's office." Tell the company to remove the loading coils and any bridging taps on your local loop and it will work. Or offer to pay for commercial ADSL service. (We'll explore the flavors of DSL in future WotDs.)

Jumper (and Jumper Cable)

Jumper:
1. A wire used to connect equipment and cable on a distributing frame.
2. Single twisted pairs used for cross connecting between 66, 110 or Krone blocks.
3. A patch cable or wire used to establish a circuit, often temporarily, for testing or diagnostics.
4. Jumpers are pairs or sets of small prongs on adapters and motherboards. Jumpers allow the user to instruct the computer to select one of its available operation options. When two pins are covered with a plug, an electrical circuit is completed. When the jumper is uncovered the connection is not made. The computer interprets these electrical connections as configuration information. When errors are found on printed circuit boards, a jumper cable is sometimes soldered in to correct the problem.


Jumper Cable: A short length of conductor or cable used to make a connection between terminals or around a break in a circuit, or around an instrument.

Patch Cord (and Panel)

Patch Cord: A short length of wire or fiber cable with connectors on each end, a patch cord is used to join communication circuits at a cross connect point. A patch cord is much like an extension cord. In the context of telephony, it's much like the cords that the telephone operators in the early 1900s used to use on a manual switchboard. They would use a short cord with a plug on each end to connect to one jack for the calling party and another for the called party. Thereby, a unique physical and electrical path was established. When the call was concluded, the operator unplugged the cord from the jacks. The next call involved a repeat of the same process, and so on. Patch cords still have a very important purpose where semi-permanent and highly reliable connections must by made between links.

Patch Panel: A device in which temporary connections can be made between incoming lines and outgoing lines. It is used for modifying or reconfiguring a communications system or for connecting devices such as test instruments to specific lines. A patch panel differs from a distribution frame in that the connections on a distribution frame are intended to be permanent.




Source: http://www.americantechsupply.com/images/CAT%206%2048%20port%20patch%20panel.jpg

Cross Connect

Cross Connect: Imagine you have an office that you need to wire up for voice and data. So you wire every desk with a bunch or wires. You punch one end of the wires into various plugs at the desk. You punch the other onto some form of punchdown block, for example a 66-block. That punchdown block may be in a closet on the same floor or it may be down in the basement. Then you bring the wires in from your telecom suppliers. The T-1s, the ATM, the FR, the local lines, the analog lines, the digital lines, etc. You punch them down on another punchdown block. Now you have two sets of blocks - one for those going to the office and those coming in from the outside world. You now have to join them in a process known as "cross-connecting" in the telecom world. You simply run wires from one punchdown device to the other. The reason you use cross-connect wires rather than just punching down an incoming phone line, for example, directly to your phone system is that moves, adds and changes would, over time, horribly confuse things, screw connections up, and eventually become a total mess. It's easier to simply have all the changes accomplished through the cross-connect wires and wiring. Follow the short wires. It's easy to see what's connected to what and provides for labeling, documentation, etc. In short, cross-connect is a connection scheme between cabling runs, subsystems, and equipment using patch cords or jumpers that attach to connecting hardware on each end. Cross-connection is the attachment of one wire to another usually by anchoring each wire to a connecting block and then placing a third wire between them so that an electrical connection is made. The TIA/EIA-568-A standard specifies that cross-connect cables (also called patch cords) are to be made out of stranded cable.

Cross Connect Equipment: Distribution system equipment used to terminate and administer communication circuits. In a wire cross connect, jumper wires or patch cords are used to make circuit connections. In an optical cross connect, fiber path cords are used. The cross connect is located in an equipment room, riser closet or satellite closet.

Cross Connect Field: Wire terminations grouped to provide cross connect capability the groups are identified by color-coded sections of blackboards mounted on the wall in equipment rooms, riser closets, or satellite closets, or by designation strips placed on the wiring block or unit. The color coding identifies the type of circuit that terminates at the field.

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.