This glossary is intended to better serve you in determining
all your voice, data and telecommunication equipment needs.
If you have any additional questions or any of these terms
need clarification, please call our Customer Service Department
NAT - Network Address Translation
An Internet standard that enables a local area network
to use one set of IP addresses for internal traffic and
a second set of IP addresses for external traffic.
A set of openings containing electrical contacts into
which an electrical device can be plugged.
Generic term for a bundle of data, usually in binary form,
organized in a specific way for transmission. A packet
consists of the data to be transmitted and certain control
information. The three principal elements of a packet include:
1. Header - control information such as address of the
destination, address of originating device, length of packet,
etc. 2. Text - the data to be transmitted. 3. Trailer -
end of packet, error detection and correction bits.
A device in which temporary connections can be made incoming
lines and outgoing lines. It is used for modifying and
reconfiguring a communications system or connecting devices
such as test instruments to specific lines. A patch panel
differs from a distribution frame in that the interconnections
on a distribution frame are intended to be permanent.
A small green box that sits outside and houses cables
coming in, cables going out and cable splices inside the
box to join the cables. This way a cable coming in from
the telephone central office can be joined to the one going
to someone's house.
The MBTN for a hunt group or distribution group. Thompson
Telephone's pilot number is 215-348-1588.
In modern buildings, the ducts carrying the heat return
are not metal ducts but are actually part of the ceiling.
This is called plenum ceiling. If you run cabling through
a plenum ceiling, you are not to use cabling sheathed in
PVC (polyvinyl chloride). When it burns, PVC emits a toxic
smoke. Plenum cable is low smoking so that if there is
a fire in your building it won’t be a hazard. Plenum
cable is often made of Teflon, so it is typically more
expensive than normal cabling.
Point of Demarcation
Physical point at which the phone company's responsibility
for the wiring of the phone line ends.
A connection with only two endpoints. It is a private
circuit, conversation, or teleconference in which there
is one person at each end, usually connected by some transmission
The physical interface between a device and a circuit.
The device may be a system, a switch or a router.
The basic service supplying standard single line telephones,
telephone lines and access to the public switch telephone
network (PSTN). There are no added features with POTS lines.
Simply making and taking phone calls.
Predicative Dialing is an automated method of making many
outbound calls without people and then passing the answered
calls to a live person. This saves the time the operator
spends reviewing records to select the person to call,
getting their phone number, dialing the number, listening
to the rings, listening to busy signals, phone company
intercepts and answering machines, and updating the record
afterwards. There are enormous productivity gains made
by automating this process and screening out incomplete
calls. Some people refer to this as Computer Aided Dialing.
Primary Interface Rate (PRI)
The ISDN equivalent of a T1 circuit. It provides 23B +
D running at 1.544 megabits per second. In ISDN, "B" stands
for Bearer, which is 64000 bits per second and can carry
voice or data. "D" stands for Delta, which is
the channel that controls all other channels in the circuit.
Private Branch eXchange (PBX)
PBX is a private (i.e. you, as against the phone company,
owns it) telephone switching system, usually located on
a customer's premises with an attendant console. A PBX
is a small version of the phone company's larger central
switching office. It is connected to a common group of
lines from one or more central offices to provide service
to a number of individual phones, such as in a hotel, business
or government office. This is also referred to as a PABX
(A stands for Automatic).
Public Switched Telephone Network (PSTN)
PSTN simply refers to the local, long distance and international
phone system that we use every day. In some countries,
it's only one phone company. In competitive companies,
like the US, PSTN refers to the entire interconnected collection
of phone companies.
Punch Down Block
A device used to connect one group of wires to another.
A 66-type block is the most common type of punch down block
(also called a terminating block, a connecting block, a
cross-connect block, a connecting block, and a quick connect
Polyvinyl Chloride, a common type of plastic used for
cladding telephone cable. See also Plenum.