Glossary

The macro-bending loss of signal in an optical fiber.

The buildings, offices, and other structures under the control of an end-user or customer.

A material

A technique or method for measuring the optical attenuation or bandwidth in a fiber by measuring first from the end and then from a shorter length and comparing the difference. Usually one is at the full length of the fiberoptic cable and the other is within a few meters of the input.

For a single-mode fiber, the wavelength above which the operation switches from multimode to single-mode propagation. This is the longest wavelength at which a single-mode fiber can transmit two modes. At shorter wavelengths the fiber fails to function as a single-mode fiber.

The count of oscillations in a wave. One cycle per second equals a hertz.

An error-checking technique used to ensure the accuracy of transmitting digital code over a communications channel after the data is transmitted. Transmitted messages are divided into predetermined lengths that are divided by a fixed divisor. The result of this calculation is appended onto the message and sent with it. At the receiving end, the computer performs this calculation again. If the value that arrived with the data does not match the value the receiver calculated, an error has occurred during transmission.

Delta channel. On ISDN networks, the channel that carries control and signaling information at 16Kbps for BRI ISDN services or 64Kbps for PRI ISDN services.

An item of hardware, usually a metal ring shaped like the letter D. It may be used at the end of a leather or fabric strap, or may be secured to a surface with a metal or fabric strap.

A type of connector that connects computer peripherals. It contains rows of pins or sockets shaped like a sideways D. Common connectors are the DB-9 and DB-25.

In telecommunications, a wiring method where each telephone jack in a building is wired in series from the previous jack. Daisy chaining is not the preferred wiring method, since a break in the wiring would disable all jacks

The external current that, under specified biasing conditions, flows in a photo detector when there is no incident radiation.

An unused fiber; a fiber carrying no light. Common when extra fiber capacity is installed.

Distributed Antenna System

With respect to data transmission, the interface that is used by a modem to communicate with a computer.