Specifications

Jitter
The deviation of a transmission signal in time or phase. It can
introduce errors and loss of synchronization in high speed
synchronous communications.
Laser
A device that transmits an extremely narrow and coherent beam
of electromagnetic energy in the visible light spectrum. Used as a
light source for fiber optic transmission (generally more expensive,
shorter lived, single mode only, for greater distances than LED).
Loop Start
The most commonly used method of signaling an off-hook
condition between an analog phone set and a switch, where
picking up the receiver closes a wire loop, allowing DC current to
flow, which is detected by a PBX or local exchange and interpreted
as a request for service.
Loopback
A type of diagnostic test in which the transmitted signal is
returned to the sending device after passing through all or part of
a communications link or network.
Manager
An application that receives Simple Network Management Protocol
(SNMP) information from an agent. An agent and manager share a
database of information, called the Management Information Base
(MIB). An agent can use a message called a traps-PDU to send
unsolicited information to the manager. A manager that uses the
RADview MIB can query the RAD device, set parameters, sound
alarms when certain conditions appear, and perform other
administrative tasks.
Master Clock
The source of timing signals (or the signals themselves) that all
network stations use for synchronization.
Multiplexer
At one end of a communications link, a device that combines
several lower speed transmission channels into a single high speed
channel. A multiplexer at the other end reverses the process.
Sometimes called a mux. See Bit Interleaving/Multiplexing.
Network
(1) An interconnected group of nodes. (2) A series of points,
nodes, or stations connected by communications channels; the
collection of equipment through which connections are made
between data stations.
Node
A point of interconnection to a network.
Off-Hook
A state that results when you lift a telephone receiver, producing a
busy signal.
Packet
An ordered group of data and control signals transmitted through
a network, as a subset of a larger message.
Payload
The 48-byte segment of the ATM cell containing user data. Any
adaptation of user data via the AAL will take place within the
payload.
Physical Layer
Layer 1 of the OSI model. The layer concerned with electrical,
mechanical, and handshaking procedures over the interface
connecting a device to the transmission medium.