Glossary

Standard 25-pin connector used with serial and parallel ports.

Standard 9-pin connector used with Token Ring and serial connections.

The total resistance of a conductor from the near end to the far end and back. For a single conductor, it is just the one-way measurement doubled. For a pair of conductors, it is the resistance from the near end to the far end on one conductor and from the far end to the near end on the other.

A standard unit used to express a relative measurement of signal strength or to express gain or loss in optical or electrical power. A unit of measure of signal strength, usually the relation between a received signal and a standard signal source. The decibel scale is a logarithmic scale, expressed as the logarithmic ratio of the strength of a received signal to the strength of the originally transmitted signal. For example, every 3dB equals 50 percent of signal strength, so therefore a 6dB loss equals a loss of 75 percent of total signal strength. See Chapter 1 for more information.

A set of waveguides having the same propagation constant for all specified frequencies.

The difference in propagation delay between the fastest and slowest pair in a cable or cabling system. See Chapter 1 for more information on delay skew.

In fiber optics, equal to the difference between the indexes of refraction of the core and the cladding divided by the index of the core.

A network access method used by Hewlett-Packard

A point where the operational control or ownership changes, such as the point of interconnection between telephone company facilities and a user

To retrieve a signal from a carrier and convert it into a usable form.

The process of separating channels that were previously joined using a multiplexer.

A device that separates signals of different wavelengths for distribution to their proper receivers.

A form of multiplexing that separates channels by transmitting them on different wavelengths at intervals of about 0.8nm (100GHz).

(1) A device that detects the presence or absence of an optical signal and produces a coordinating electrical response signal. (2) An optoelectric transducer used in fiber optics to convert optical power to electrical current. In fiber optics, the detector is usually a photodiode.

Occur when the detector is unable to make an intelligent decision on the presence or absence of a pulse due to the losses that render the amplitude of the pulse too small to be detected or due to excessive noise caused by the detector itself.