Amplifier

When telephone conversations travel through a medium, such as a copper wire, they encounter resistance and thus become weaker and more difficult to hear. An amplifier is an electrical device which strengthens the signal. Unfortunately, amplifiers in analog circuits also strengthen noise and other extraneous garbage on the line. Cascading amplifiers, therefore, compound, or accumulate, noise. Digital systems make use of regenerative repeaters, which regenerate (i.e. reshape or reconstruct) the signal before amplifying it and sending it on its way. As a result, noise is much less prevalent and less likely to be amplified in digital systems, whether one or many repeaters are in place. The ultimate yield of a repeater in a digital environment is that of improved error performance, which also yields improved throughput, assuming that error correction involves retransmission.

Repeater Coil (and Repeater)

Repeater Coil: Also called a Repeat Coil. It's really just a transformer, which converts AC power to the voltages used to charge batteries and to power various devices such as PBXs. Repeater coils also are used for impedance matching, which serves to maximize the power transfer of a signal where two electrical circuits (e.g, twisted pair) are interconnected. The power transfer is improved through the elimination of echo, which is signal reflection back towards the signal source.

Different than a Repeater…

Repeater: Also known as a Regenerative Repeater and a Regenerator. A device inserted at intervals along a digital circuit to regenerate the transmitted signal. As the digital signal transverses the circuit, it loses its shape due to the combined effects of attenuation and noise. Attenuation is weakening of the signal as it transverses the circuit. Noise, or distortion, can be caused by EMI (ElectroMagnetic Interference), RFI (Radio Frequency Interference) frequency shifts internal to the circuit, and various other factors. At some point, the original signal becomes incoherent unless a repeater is placed on the circuit at specific intervals, which are sensitive to the specifics of the circuit design. The repeater is capable of reading the signal, even though it is somewhat attenuated and distorted, reshaping it into proper "ones" and "zeros," and repeating (i.e., retransmitting) it at the proper level of signal strength. Repeaters are used exclusively in digital circuits, whether they are metallic (e.g., twisted pair and coaxial), radio (e.g., cellular, microwave, and satellite), or optical (e.g., optical fiber). Analog circuits make use of amplifiers, which simply serve to boost the signal strength, and which cannot reshape it.

Loop Extender

Device in the CO (Central Office) that supplies augmented voltage out to subscribers who are at considerable distances. It provides satisfactory signaling and speech for such subscribers. More specifically, an ADSL (Asymmetric Digital Subscriber Line) loop extender increases the channel capacity of a DSL connection from the CO to the subscriber. ADSL repeaters are aggressively deployed by rural telephone companies trying to reach farms and small towns in areas where it is impractical to place the DSLAM (DSL Access Multiplexers) closer. The typical distance improvement with a loop extender is shown in the diagram below, with rate in Megabits per second and distance in thousands of feet. In future WotD's we will explore in more detail DSL (and ADSL) along with the market for these services.

For graph visit: http://www.strowger.com/images/moz-screenshot-8.jpg

[Note: ADSL2 and ipTV in this sense, refer to types/levels of service offered to DSL subscribers]

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.