Digital Equipment DECconcentrator 500, Installation Manual, Page: 89 / 98

Glossary–3
fiber optic cable
A transmission medium designed to transport signals in the form of pulses of light.
fiber optics
A technology whereby signals are transmitted over an optical waveguide medium
through the use of light-generating transmitters and light-detecting receivers.
LASER
Light Amplification by Stimulated Emission of Radiation. Predominantly used for
transmission over single-mode cables systems.
MAC
See Media Access Control.
Media Access Control (MAC)
The Data Link sublayer responsible for scheduling, transmitting, and receiving data
on a shared medium local area network (for example, FDDI).
Network Management Card
An option card for the concentrator that provides for the connection to the dual ring
and the hardware/firmware to allow remote management. A Network Management
Card has two ports and two switches.
optical receiver
An optoelectronic circuit that converts an incoming optical signal to an electronic
logical signal; typically a photodetector.
optical transmitter
An optoelectronic circuit that converts an outgoing electronic logical signal to an op-
tical signal; typically a light emitting diode or laser diode.
PHY
See Physical Layer Protocol.
physical connection
The full-duplex physical layer association between adjacent PHYs in an FDDI ring;
a pair of physical links.
Physical Layer Protocol
FDDI standard that defines symbols, line states, clocking requirements, and encod-
ing of data for transmission.
physical link
The path, through PMD and attached cabling, from the logic of one PHY to the re-
ceive logic of an adjacent PHY in an FDDI ring.