Nortel RLC Installation And Administration Manual page 434

Glossary
Private Branch Exchange
A telephone switch, typically used by a business to service its internal telephone
needs. A PBX usually offers more advanced features than are generally
available on the public network. Users of the PBX share a certain number of
outside lines for placing telephone calls external to the PBX.
protocol
A standard format used for communication between two devices. The protocol
determines the type of error checking to be used, the data compression method
(if any), how the sending device will indicate that it has finished sending a
message, and how the receiving device will indicate that it has received a
message.
PSTN
Refer to Public Switched Telephone Network.
Public Switched Telephone Network
Any common carrier network that provides circuit switching between public
users. The term is usually applied to the public telephone network.
Q
Quality of Service (QoS) Transitioning Technology
Nortel's patented technology that can automatically switch calls from the IP
network to the PSTN when the voice QoS falls below a predetermined threshold,
and back to the IP network when the QoS returns to normal.
R
RAM
Random Access Memory. This is the most common type of memory found in
computers and other devices, such as printers. The term RAM is usually
synonymous with main memory, the memory available to programs. For
example, a computer with 8 Mbytes of RAM has approximately 8 million bytes
of memory that programs can use.
RAS
Remote Access Server. A host on the local area network that is equipped with
modems to enable users to connect to the network over telephone lines.
408 RLC Installation and Administration Guide
Standard 4.0