Black Box 5000 - Manual (Page 259)

Glossary
257
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.
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.)