Black Box 5000 manual FDX See full-duplex, ISU, integrated service unit An integral interface

Multiserver network. On incoming calls, the fax signals are routed automatically from either the PSTN or the Multiserver network to the fax machine. On outgoing calls, the desired destination network for the fax machine is selected by the user.

FCC — A government board that has the power to regulate all U.S.A. interstate communications systems as well as all international communications systems that originate or terminate in the U.S.A.

FDX — See full-duplex.

feeder mux — Any compatible multiplexer attached to a Multiserver unit. All of the ports of a feeder mux are addressable by the network so that connections can be made on an individual basis.

FF, form feed — A control character used to tell a terminal device to go to the top of the next page.

flow control — The procedure for controlling the transfer of data between two points in a data network, such as between a terminal and a multiplexor, to prevent loss of data when the receiving device’s buffer reaches its capacity.

forced connection — A dedicated connection between two channels in the network. Contrast with switching.

four-wire circuit or four-wire line — A circuit using two pairs of conductors, one pair for the transmit channel and one pair for the receive channel.

fox message — A test message (THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG. 1234567890), that contains all the letters of the alphabet and all the numerals. This is usually produced in the fox-message generator in a Multiplexor.

full-duplex— Simultaneous two-way independent transmission.

Glossary

half-duplex— Transmission in one direction at a time.

hardware reset — Resets date and time but retains the current configuration. This reset is accessed from the front of the Multiserver.

HDX — See half-duplex.

header — Pins on a circuit board on which a

jumper can be installed for hardware configuration purposes.

host — The central computer (or computer systems) that provides primary data processing functions.

hub group — This term is most often used in discussions of switching. A Multiserver 5000 unit and all attached feeder muxes are considered a hub group.

Hz, hertz — A measure of frequency or bandwidth equal to one cycle per second. Named after experimenter Heinrich Hertz.

indicator lights — The light emitting diodes (LEDs) on the front of the Multiserver unit.

input level — A level of relative analog signal strength obtained from the attached telephone equipment, as measured in the voice/fax module.

input level display — A visual indication of the input level as displayed by the voice/fax module. Used as a diagnostic tool to monitor the input signal level.

interconnect link — A Multiserver-to-Multiserver composite link using ESI Protocol.

ISU, integrated service unit — An integral interface

device that combines the functions of a DSU and a CSU. The 56K CSU/DSU module is an ISU.

jumper — A miniature connector that fits over, and electrically connects two pins.

Kbps, kilobits per second — One thousand bits per second. (Example: 19,200 bps is 19.2 Kbps.)

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