F I M - 1 0 8 F I B E R I N T E R F A C E
4 - 1
GLOSSARY
fiber-optic cable
A fiber-optic cable consists of a glass core covered with a
reflective material called “cladding” and several layers of buffer coating to protect
the cable from the environment. A laser sends light pulses through the glass core
to the other end of the cable.
full duplex
Refers to transmission of signals in two directions simultaneously.
interface
A piece of electronic hardware designed to convert the 4-wire signals
of a central matrix port to some other form of communications, such as 2-wire
party line, telephone, etc. The interface is connected to a central matrix port.
The external non-4-wire device is then connected to the interface.
mode
A term used to describe a light path through a fiber, as in multimode or
single mode.
multimode fiber-optic cable
The glass core of a multimode fiber is larger
than the core of a single mode fiber, which causes the transmitted light beam to
disperse as it travels through the core. Single mode fiber, with its smaller core,
concentrates the light beam so that it carries signals further. Multimode fiber was
the first type of fiber offered by manufacturers. Single-mode fiber evolved as
production methods improved.
multiplexing
The process by which two or more signals are transmitted over a
single communications channel. Examples include time division and wavelength
division multiplexing.
nanometer (nm)
Common unit of measure for wavelength. One billionth of
a meter.
optical signal
A laser at one end of a fiber-optic cable pulses on or off to send a
light signal through the glass core of the cable to the other end of the cable.
Because the light signals are binary (on or off ), the signal is digital.
port
Any of the input/output connections (RJ-45 connectors) on the back panel
of the central matrix. These connectors, and the attached cables, connect the
central matrix to remote intercom devices. The term “port” emphasizes that the
connection is a “portal” between the central matrix and the remote intercom
devices.
remote station
Any intelligent intercom device connected to the back-panel
ports of the central matrix. This term does not refer to devices connected
through interfaces.
single-mode fiber-optic cable
The glass core of a single-mode fiber is
smaller in diameter than the core of a multimode fiber, so that the light signal
transmitted over the core is more concentrated than with multimode fiber,
which allows the signal to travel further. Single-mode fiber evolved from
multimode fiber as production methods improved.
4
