TC Communications TC8518 T1, Руководство пользователя

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Glossary-4 TC8518 Rev 2.2 User Manual
O
OSI
(Open Data Interconnection Reference Model) - This is the International
Standards Organization (ISO) model of how data communications systems can be
interconnected. Communication is partitioned into seven function layers. Each
layer builds on the services provided by those under it.
P
Packet
A grouping of data, usually consisting of data and an address header prior to
being sent over a network.
Polling
The method used for terminal to controller communications. The controller
systematically asks for each terminal if it needs to transmit to the controller.
Protocol
A set of rules for data communication. All devices communicating together must
adhere to the same rules.
PWR
The Power Source A and B are continuously monitored in the event of a
failure. This LED indicates the condition. See
SNMP Query, on page 5-1.
Q
QoS
Quality of service.
In the field of computer networking and other packet-
switched telecommunication networks, the traffic engineering term quality
of service (QoS) refers to resource reservation control mechanisms rather
than the achieved service quality. Quality of service is the ability to provide
different priority to different applications, users, or data flows, or to guar-
antee a certain level of performance to a data flow.
R
DIN Rail
A DIN rail is a metal rail of a standard type widely used for mounting
circuit breakers and industrial control equipment inside equipment racks.
Reserve Space
Reserve space is the distance between the cables or unit that allows for
human access, cables bends that will not harm connections, and air flow.
Ring
Path or channel; usually electrical, where devices along the path receive
transmissions sequentially
from one device to the next along the ring.