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THE PCIA WIRELESS MARKET PORTFOLIO
GLOSSARY OF TERMS
ABBREVIATED DIALING - A feature where the user can effect dialing of stored, called
numbers by using a
two-, three-, or four-digit code instead of the entire seven or ten number sequence. Also
called speed dialing.
ACCESS CHARGE - Cost to user for access to interexchange, interstate message toll
telephone network to originate and receive
interstate toll calls, as well as interexchange carrier access to the user's Local Access
Transport Area (LATA).
ACCESS CODE - Extra digit of digits that a PBX extension user must dial to obtain a
specific service.
ADVANCED MOBILE PHONE SERVICE (AMPS) - AT&T-developed analog cellular
radio standard, adopted in the U.S.
and in many other parts of the world.
ALARM DISPLAY - Indicator's on attendant's console that display system status. Usually
two alarms included: minor alarm to
signal a malfunction in a part of the system and major alarm to indicate that system will
not work at all.
ALARMS SIGNALS TO STATIONS - Indicates the ability of the system to interface
with various types of signalling systems and
to transmit such alarms in the form of coded tones.
ALGORITHM - A logical or mathematical model that incorporates a specific set of rules
that tell how information is to be
manipulated to give a desired result. It is a fancy word for a model. Distinguishing
between the model and the real situation is critically
important, because the differences often explain why a properly executing program gives
erroneous or non-useful results.
ALL NUMBER CALLING (ANC) - Calling by means of seven digits instead of the
previously used two letters plus five digits.
ALL TRUNKS BUSY (ATB) - A condition in which all trunks in a given trunk group are
busy.
ALPHANUMERIC - A character set containing letters, digits, and other symbols such as
punctuation marks.
ALPHANUMERIC DISPLAY FOR ATTENDANT CONSOLE - Feature in which
attendant console provides visual readout
of incoming call source.
AMPLIFIER - Used to boost sound in analog systems.
AMPLITUDE - Magnitude or size. In waveforms (signals you prefer) occurring in a data transmission, the waveform can be completely defined if the voltage level is known at all times. In this case, the voltage level
is called the amplitude. The word is a handy,
elegant way of referring to the magnitude of something.
ANALOG TRANSMISSION - Transmission of a continuously variable signal as
compared to a discrete (digital) one.
ANCILLARY EQUIPMENT - Equipment added on to a basic telephone system to
provide enhanced features.
ANTENNA (BI-DIRECTIONAL) - Antenna that radiates most of its power in two
directions.
ANTENNA (OMNI-DIRECTIONAL) - Antenna that radiates equal power in all
directions in a horizontal plane.
ANTENNA (UNI-DIRECTIONAL) - Antenna that radiates most of its power in one
direction.
ASCII - American Standard Code for Information Interchange. Also called USASCII in
an attempt to follow the name changes of
the USA standards body; the last name change to ANSI was not followed. Although
adopted in the early 1960's as a universal
computer and communications code and, for a while, strongly supported by the U.S.
government, the code has had limited usage
outside of teleprinters and display terminals by vendors other than IBM. Possibly, the code
has survived because of the large
Teletype printer base. Originally, it was a seven-letter code. Later, an eighth bit was
added, usually to represent character parity.
Now, parity is a standard part of the code.
ASYNCHRONOUS TRANSMISSION - A communications system in which units of data
are sent a character at a time preceded
and followed by start/stop signals which provide timing at the receiving terminal. Also
called start/stop transmission.
ATTENDANT DIRECT PAGING - Direct access control(s) are provided on the console
or chord switchboard for voice paging.
ATTENDANT - Usually refers to a local switchboard operator, for example, on a PBX.
ATTENUATION - The difference between transmitted and received power due to loss
through equipment, lines, or other
transmission devices. It is measured in decibels.
ATTENUATION VALUES - Decrease in power of a received signal.
AUTOMATIC DIALER - Device that allows a caller to push one preprogrammed button
instead of 7 or 10 numbers.
AUTOMATIC HANDS-FREE TALKBACK - On stations which have built-in speakers,
this facility allows direct access to a
given station via the intercom facility when the station is busy on an "outside" call.
AUTOMATIC NUMBER IDENTIFICATION (ANI) - A service feature whereby the directory number or equipment-number of a calling station is obtained automatically, for use in message accounting. BACKBONE NETWORK - Transmission facility, or arrangement of such facilities,
designed to interconnect lower speed
distribution channels or clusters of dispersed users or devices.
BAND - 1)The range of frequencies between two defined limits. 2) The specific
geographic area which the customer is entitled to
call in a Wide Area Telephone System (WATS).
BANDPASS LIMITER - A device that imposes hard limiting on a signal and contains a
filter that suppresses the unwanted
products of the limiting process.
BASE STATION - Fixed radio station used by RCC's to send, receive, and transport
signals.
BASEBAND SIGNALLING - Transmission of a digital or analog signal at its original
frequencies.
The signal is in its original form, not changed by modulation.
BAUD - A unit of signalling speed. The speed in baud is the number of discrete conditions
or signal elements per second.
BELL OPERATING COMPANY (BOC) - One of the 22 Bell telephone companies
whose primary business is providing local
telephone service to customers. They are allowed to market, but not manufacture, new
equipment.
BIT - A contraction of Binary Digit. It is the smallest unit of information in a binary
system.
BITS PER SECOND (BPS) - Rate at which bits are transmitted.
BLOCK - A group of characters of bytes transmitted as a unit.
BLOCKING - The inability to complete a call because all possible paths between the two
calling stations are already in use.
BROADBAND - Referring or pertaining to an analog circuit that provides more
bandwidth than a voice grade telephone line, i.e., a
circuit that operates at a frequency of 20KHz or greater. Broadband channels are used for
high-speed voice and data
communications, radio and television broadcasting, some local and data networks, and
many other services. Also called wide-band.
BROADCAST - 1)Delivery of a transmission to two or more stations at the same time
such as over a bus-type local network or by
satellite. 2) Protocol mechanism whereby group and universal addressing are supported.
BUSY HOUR - The 60-minute time span during the day with the maximum average
traffic density.
BYTE - A computer-readable group of bits, normally 8, 16, or 32 bits in length. CABLE - An assembly of one or more conductors or optical fibers within an enveloping
sheath, constructed so as to permit use of
the conductors singly or in groups.
CALL ACCOUNTING SYSTEM - Device that tracks outgoing calls and records data for
reporting.
Also called Station Message Detail Recording (SMDR).
CALL FORWARDING BUSY LINE - Automatically reroutes incoming calls directly to
the attendant or predetermined secondary
station when the called station is busy.
CALL FORWARDING DON'T ANSWER - Automatic rerouting to a secondary station
or attendant when a given station does
not answer with a prescribed time interval (the exact interval depends on the type of
switching system, but it is generally about 30
seconds).
CALL FORWARDING - This feature allows a station user to program at any time any
internal station number (or the attendant)
and, when activated by the station user, all incoming calls to his station will be
automatically rerouted to that preprogrammed number.
CALL HOLD - A feature that allows a station user to hold any call in progress on that
station line by flashing the switchhook, dialing
a second digit such as "1," or depressing a special station pushbutton that will
automatically provide a second dial tone for the
purpose of originating another call.
CAPACITY - The average amount of traffic that a circuit or circuit group can handle.
CAPTURE EFFECT - In FM reception, when stronger of two stations at or near the same
frequency suppress the weaker one.
CARRIER (CXR) - 1) Continuous frequency capable of being modulated, or impressed,
with a second information carrying signal.
CARTERFONE DECISION - A 1968 landmark FCC ruling that extended the 1956 Hush-A-Phone Decision to include the
interconnection of all types of telephone equipment to the public-switched network. The
decision allowed telephone subscribers to
own and use telephone equipment providing it was not technically harmful to the network.
CELLULAR MOBILE TELEPHONE SERVICE - A type of mobile telephone service in
which the geographic serving area is
divided up into subregions (or cells), each with its own antenna and switching node.
CENTRAL OFFICE (CO) - Local telephone company's centralized switching equipment
and outside plant where calls are
switched over the local network or onto a long-distance network.
CHANNEL - A path for electrical transmission between two or more points without
common carrier-provided terminal equipment;
also called a link, line, circuit, or facility.
CHARACTER - A unit of information, usually associated with people-language style of
presenting information. Because so much
data is handled and transferred in this style, the term is also frequently used to mean one
bit pattern in a particular data code.
CHARGER/AMPLIFIER - Allows owner of a pager to program the pager's address.
CHURN - Annual turnover/replacement of pager units among subscribers.
CIRCUIT - Physical connection of channels, conductors, and equipment required to
provide a complete communications pathway.
CIRCUIT SWITCHING - Physical interconnection between two circuits or channels. The
term is in contrast with message
switching.
COMMON CARRIER - A government-regulated company responsible for the provision
of telecommunications services in a given
territory, providing users, at a cost, with access to communications.
COMPUTER II - 1980 FCC ruling that established a framework for the transition to open
and competitive CPE and enhanced
transmission services markets. The Computer II decision ordered the provision of non-basic or "enhanced services" and CPE to be
detariffed, and required the then-integrated Bell System to establish a fully separate
subsidiary for the marketing of such services.
COMPUTER III - 1986 FCC ruling that removed the separate subsidiary requirement for
both AT&T and BOC provision of
enhanced services.
COMPUTER MAIL SYSTEMS - E-Mail systems which employ centralized "post offices"
on host computers. Satellite computer
terminals can access the post office to read, answer, forward, file or delete waiting
messages.
CONSOLE DIGITAL DISPLAY (Terminal) - When a page is initiated, a digital display at
the console indicates the identification
number of the pager being alerted.
CROSS-TALK - Energy leak from one channel to another. On the telephone network you
hear somebody else's conversation. If
transmitting data, a noise source.
CUSTOMER PREMISES EQUIPMENT - Any apparatus - including telephone handsets, PBX switching equipment, key and hybrid telephone systems, and add-on devices - that is physically located on a customer's property, as opposed to being housed in the telephone company's central office. DATA - A singular noun meaning information. (Originally the plural form of the Latin
noun datum; if you transmit Latin, use data as a
plural noun.)
DECIBEL (db) - Unit for measuring relative strength of a signal parameter such as power,
voltage, etc.
DEMODULATION - Process of retrieving data from a modulated carrier wave.
DEREGULATION - The reduction in tariff, market entry and exit, and facilities
regulation of public telecommunications services in
response to competitive and technological pressures from the telecom industry.
DIAL ACCESS TO PAGING - Pages can be initiated from any tone signalling telephone
with access to terminal equipment.
DIALTONE - A signal heard when the telephone handset is off the hook indicating that
the central office is ready to accept and
process a dialed number.
DIGITAL BIT STREAM - A series of bits, or on/off signals.
DIGITAL - Referring to communications procedures, techniques, and equipment whereby
information is encoded as either binary
"1" or "0"; the representation of information in discrete binary form, discontinuous in time,
as opposed to the analog representation of
information in variable but continuous waveforms.
DIGITAL SIGNAL - Transmission signal that carries information in a discontinuous
stream of on/off pulses.
DIGITAL SWITCH - Switching equipment designed, designated or used to perform
switching of digital switches.
DIGITAL SWITCHING - A process in which connections are based on digital signals
without converting them to analog signals.
DIRECT INWARD DIALING (DID) - Method of connecting calls originating on the
public switched telephone network directly
to dial specified stations on a PBX system.
DIRECT OUTWARD DIALING (DOD) - Method of connecting stations on a PBX
system to the public switched telephone
network through the use of the station dial equipment only.
DISCONNECT - The disassociation or release of a switched circuit between two stations.
DISTORTION - Unwanted change in waveform that occurs in between points in a
transmission system.
DISTRIBUTED PROCESSING - A general term, usually referring to the use of
intelligent or programmable terminals at sites
remote from a company's main computer facility. The difficulty associating a precise
definition with the term stems from the source of
the concept-i.e., the programmability of the terminal. Because such programmability can
be used to provide component control, line
control, data formatting, date validation, data manipulation, and computation (processing),
file creation, and file manipulation (also
data processing, terminal programmability itself is insufficient to identify distributed
processing.
DIVESTITURE - Under the terms of the MFJ, AT&T relinquished ownership and control
of the local Bell telephone operating
companies.
DOWNLINK - A link from a satellite to an earth station.
DOWNTIME - Total time a signal is out of service due to equipment failure.
DUAL TONE MULTIFREQUENCY (DTMF) - Method of signalling (dialing) using a
tone pad. Each digit dialed generates a
unique frequency which the central office is programmed to recognize as a particular digit.
DUPLEX - Simultaneous transmission in both directions; synonymous with full duplex.
DYNAMIC COVERAGE CONTROL - Feature which allows paging subscribers to select geographic locations, including the entire paging area, in which they will be paged. EARTH STATION - Equipment on the ground that sends/receives signals to/from
satellites.
ELECTROMAGNETIC COMPATIBILITY (EMC) - The capability of
telecommunications equipment, subsystems, or or
systems to operate in their intended operational environments without suffering or causing
unacceptable degradation because of
electromagnetic radiation or response.
ELECTROMAGNETIC INTERFERENCE (EMI) - Radiation leakage outside a
transmission medium that results mainly from
the use of high-frequency wave energy and signal modulation. EMI can be reduced by
appropriate shielding.
ELECTRONIC MAIL - Any communications service that permits the electronic
transmission and storage of text messages.
ELECTRONIC SWITCHING - Switching technology based on the use of microprocessor
chips and integrated circuits.
END OFFICE - A local exchange office where the user's loop terminates.
ENHANCED SERVICE - The combination of "basic" service with computer processing
applications that results in a modification
of the transmitted information.
ERROR - Any change from the original. In data communications, error often refers to
detected error.
EXCHANGE - A switching center, or the area where a common carrier furnishes service at the exchange rate and under the regulations applicable in that area as prescribed in the carrier's filed tariffs. FACILITIES-BASED CARRIER - Interexchange carriers which own their network
facilities and transmission lines.
FACILITY - Transmission path between two or more points, provided by a common
carrier.
FACSIMILE - Technology that allows a paper message to be scanned optically, translated
into digitally encoded pixels (patterns of
tiny light and dark spots), and sent across the public telephone network to a receiving
facsimile machine which reconstructs the
original image.
FEDERAL COMMUNICATIONS COMMISSION (FCC) - An independent federal
agency, authorized by the
Communications Act of 1934, responsible for regulating interstate and foreign
telecommunications.
FIBER-OPTIC SYSTEMS - Telephone transmission media using strands of clear glass
fibers to carry hundreds of thousands of
voice circuits. The signals are transmitted as light pulses.
FILTER - In telecom, equipment that permits the transmission of certain frequencies while
excluding others.
FOOTPRINT - 1) Surface area within which the strength of a projected beam is above a
certain level. Usually used in satellite
communications to refer to the area where downlink signals above a minimum quality level
can be received. 2) Amount of desk top
space a piece of equipment (e.g., a terminal) requires.
FREQUENCY MODULATION - Carrier transport technique that shifts thecarrier
frequency by an amount proportional to the
value of the modulating signal.
FREQUENCY SHIFT - Modulation method that causes the frequency to vary at
significant instants.
FREQUENCY - The rate at which current alternates.
FREQUENCY-DIVISION MULTIPLEXING - A space-division multiplexing technique
in which the available transmission
frequency range of a given circuit is divided into narrower bands, each use to carry a
separate conversation.
FRONT-END NETWORKING - Method for national and regional paging in which a
network intercepts paging messages before
they reach facilities of an RCC or other conventional paging service provider. The
network then routes messages to the appropriate
transmitting facilities, either locally or in various distant locations.
FSK - Frequency shift keying. A common form of modulation using two separate
frequencies to represent the two binary digits.
FULL-DUPLEX - A circuit or device that permits transmission in two directions at once. GAIN - An increase in signal power denoted in dBs.
GATEWAY -An important characteristic of a LAN that allows it to interface with
different transmission networks, particularly the
public switched telephone network. The interface mechanism provides a special data
translation and conditioning functions for
transmission compatibility between the networks.
GOLAY SEQUENTIAL CODE - A digital signalling protocol, developed/specified by
Motorola.
GROUP CALL (Terminal) - Group of pagers can be alerted with a single call. HALF-DUPLEX -A circuit or device capable of transmission in two directions, but not
simultaneously.
HANDOFF - In a cellular radio system, the process of transferring a phone call in progress
from one cell transmitter to another using
a different frequency without interruption of service.
HERTZ (Hz) - Unit of frequency equal to one cycle per second. INDEPENDENT TELEPHONE COMPANY- A company not fully or partly owned by
AT&T. The term is now archaic since
the BOC's became independent.
INTEGRATED CIRCUIT - A multifunction circuit formed in or around a semiconductor
base.
INTEGRATED SERVICES DIGITAL NETWORK (ISDN) - The technical standards
according to the all-digital local
exchange will be designed. ISDN will provide a high-speed, high-bandwith channel to
every subsriber on the telephone network,
achieving end-to-end digital functions with standard equipment interface devices.
INTEGRATED SYSTEM - A system that transfers analog and digital traffic over the
same switched network.
INTELSAT - International Telecommunications Satellite Consortium, formed in 1964
with the goal of creating a world wide satellite
system.
INTERCONNECT - Any company other than the local phone company that supplies
equipment for connection to phone company
lines by sale, lease or rent.
INTERCONNECT FACILITY - One or more communications links used to provide local
area communications service between
or among several locations which, taken as a whole, form a node in the network.
INTERFACE - A bounded area between two pieces of equipment by which all signals that
pass through are carefully defined.
INTERSTATE - Between two or more states.
INTRASTATE - Within one state. LINE - A transmission wire within a telephone system; part of a local loop that connects a
subscriber to the central office.
LOCAL ACCESS AND TRANSPORT AREAS (LATAs) - Local telephone network
areas controlled and operated by the
BOCs.
LOCAL AREA NETWORK - A high-speed data communications systew with all aspects
of a transmission medium controlled by
a network operator. LANs typically permit the user to connect several diverse
telecommunications and office equipment funtions into
one integrated system.
LOCAL EXCHANGE AREA - That part of the national telephone network controlled by
the local telephone operating company
and separate from the long-distance network. Local exchange areas are generally
regulated by the state public utility commission.
LOCAL LOOP - Telephone wires and other facilities that link local subscribers to the local telco's central office. MAINTENANCE - The necessary upkeep and repairs needed to maintain a level of
quality for the service.
MESSAGE - A loose term identifying a complete transmission. It is sometimes used
synonymously with block, and sometimes to
mean a group of blocks representing one transmission period. Control information at the
beginning is usually referred to as a header;
the data portion is normally referred to as the text.
MESSAGE ENTRY DEVICE (MED) - A device which sends information into a paging
network using TDP. This may be any
type of device from a hand-held unit to a host computer.
MICROWAVE RADIO - A radio frequency used extensively for long-distance telephone
transmission. Digitally encoded
messages are sent thorugh microwave channels either between terrestrial antenna, via
satellite, or through waveguides.
MOBILE COMPUTING DEVICE - The ultimate recipient of the date entered from the
message entry device.
MOBILE TELEPHONE SERVICE - Transmission over the public switched network of a
voice signal that originates an/or
terminates at a mobile site. The process involves radio signals transmitted to a centrally
located antenna attached to a mobile
telephone switch.
MODEM - Device that modulates discontinuous digital signals into continuous analog
waves for transmission over analog circuits,
and then demodulates the waves into digital bit streams at the receiving end of the circuit.
MODIFIED FINAL JUDGEMENT - 1982 agreement between the Department of Justice
and AT&T which called for the
divestiture of the local Bell telephone operating companies by AT&T.
MODULATION - Impressment of information on a carrier signal by varying one or more
of the signal's basic characteristics:
frequency, amplitude, and phase. Differential modulation carries the information as the
change from the immediately preceding state
rather than the absolute state.
MULTIPLEXER - A device that combines several communication channels into a single
circuit.
MULTIPOINT - Three or more stations connected to the same facility. It implies that the facility physically goes from one station to another until all are connected. NACK - A negative acknowledgement that indicates a block of data was received
incorrectly.
NARROWBAND - A channel with a bandwidth of less than one voice grade.
NATIONWIDE PAGING - A method of national or regional paging in which a single
frequency is used throughout the nation or
region for sending messages to a paging subscriber.
NETWORK 1) Series of points connected by communications channels. 2) Switched
telephone network is the network of telephone
lines normally used for dialed telephone calls. 3) Private network is a network of
communications channels confined to the use of one
customer.
NETWORKING - Method of national or regional paging in which paging messages are
sent via a communications network to
various regions and transmitted, usually at different frequencies and different areas.
NODE - A termination point for two or more communications links. The node can serve
as the control location for forwarding
(switching) data among the elements of a network or multiple networks when networking.
Node functions need not be restricted to
data switching.
NXX - Code that designates a specific central office. "N" is any number from 2 to 9. "X" is any number from 0 to 9. OPERATOR - Person who assists in placing telephone calls.
ORIGINAL EQUIPMENT MANUFACTURER (OEM) - Maker of equipment that is
marketed by another vendor, usually
under the name of the reseller. The OEM may only manufacture certain components, or
complete computers, which are then often
configured with software, and/or other hardware by the reseller.
OUT OF BAND SIGNALING - The transmission of signaling via a different channel (either FDM or TDM) than is used for the primary information transfer. PABX - Private Automatic Branch Exchange, now used interchangeable with PBX.
PACKET SWITCHING - Data transmission technique in which data messages are divided
into blocks, or packets, of standard
length each of which has address and control information coded into it.
PAGER - Pocket size radio receiver which generates audible or physical signal when user
is paged.
PAGER PRINTER (Receiver) - Small printer that issues printed record of a paging
message.
PAGING BY ZONE - The ability of a station to selectively page groups of predesignated
stations by dialing the appropriate access
code.
PAGING MESSAGE PROCESSOR - A radiopaging terminal.
PAGING SPEAKERS - The inclusion of such speakers within the station instrument.
PART 68 - The FCC rules regulating the direct connection of non-telephone company-provided equipment to the public telephone
network.
PLAIN OLD TELEPHONE SERVICE (POTS) - The basic suppliance of a single
telephone set with access to the public switched network.
POCSAG - A digital signaling protocol developed and specified by the British Post Office.
Also known as CCIR #1.
POINT-TO-POINT - Describing a circuit that connects two points directly, where there
are generally no intermediate processing
nodes or computers, although there could be switching facilities. A type of connection,
such as a phone line circuit, that links two, and
only two, logical entities.
PRIVATE BRANCH EXCHANGE (PBX) - A private telephone switching system
located on a customer's premises. Both PBX
and hybrid PBX systems provide pooled access to a group of access lines typically by
dialing "9" from an internal station set.
PROTOCOL - The rules of order by which a communications network is operated. Also,
the rules by which a specific data
communications function must proceed.
PTT - Postal, telegraph and telephone organization. Usually the governmental office that
runs a foreign nation's communication
system.
PUBLIC SWITCHED TELEPHONE NETWORK (PSTN) - The domestic
telecommunications network commonly accessed by
ordinary telephones, key telephone systems, PBX trunks, and data arrangements.
PUBLIC UTILITIES COMMISSION - State regulatory administrative body that directs
intrastate utilities, including
telecommunications. Also known as Public Service Commission.
PULSE - A signal that can be wholly described by a constant amplitude and the duration
time. This signal form is typically used
internally in computers, terminals, and other business machines, but is also used by some
communications facilities.
PULSE AMPLITUDE MODULATION (PAM) - Technique in which an analog speech
signal is sampled at specific short
intervals, and a numerical value representing the magnitude of the wave's amplitude at that
point is assigned to each sample. The first
step in pulse-coded modulation.
PULSE-CODED MODULATION (PCM) - The most frequently used method of
converting analog signals into digital bits. The
process involves transforming an analog wave into quantified steps, assigning the steps a
discrete set of values and coding these values
into a digital bit-stream. At the receiving end, the digital codes are transformed back into
analog values and the original signal is
reconstructed.
PUSH-TO-TALK OPERATION - Method of communication over a speech circuit in which transmission occurs from only one station at a time, the talker being required to keep a switch operated while talking. RADIO COMMON CARRIER (RCC) - Independent radio paging and mobile
telecommunications companies that provide
FCC-approved communications services through transmission of radio signals.
RATE - The price charged for telecommunication service or equipment.
REAL TIME - Processing now, without delay. It is used by engineers to indicate
processing in time to control an event, and by data processing personnel to indicate processing transactions as they occur.
RECEIVER - A device on the transmission line that converts a signal to whatever type of
signal is neede to complete the
transmission.
REDUNDANCY - Ancillary information, not directly essential though pertinent to a set of
information. Also, the state of providing
redundant or backup components to ensure uninterrupted operation of a system in case of
failure.
REGIONAL HOLDING COMPANY (RHC) - One of seven firms created from the
AT&T divestiture, each of which acts as a
holding company within a region of the United States for one or more of the twenty-two
divested Bell operating companies, as well as
for their unregulated subsidiaries.
REPEATER - Apparatus that automatically retransmits signals on an outbound circuit.
RESALE CARRIERS - Interexchange carriers that lease transmission facilities and resell
them to the general public.
RF RECEIVING DEVICE - The radio receiving device which receives over-the-air data
and forwards this information to the
Mobile Computer.
ROTARY - A type of telephone dialing via a series of electrical impulses to the central
office.
RS-232 - A technical specification published by the Electronics Institute Association that establishes interface requirements between modems, terminals, or computers, and communications lines. SATELLITE COMMUNICATIONS - An orbiting system in space that receives radio
signals from the ground and then
retransmitts them to distant locations.
SIDEBAND - The bands of frequency above and below a carrier frequency which are
produced by its modulation.
SIGNAL-TO-NOISE RATIO - Relative power of the signal to the noise. As the ratio
decrease on a line, it becomes more difficult
to distinguish between information and non-information (noise).
SIGNALING - The process by which a dialed number is routed through the telephone
network and a connection is made between
two stations.
SIMPLEX - A circuit or device that permits transmission in one direction only.
SPECIALIZED MOBILE RADIO (SMR) - Private trunked two-way mobile radio system
to which multiple users have access.
SPREAD SPECTRUM - A communications technique in which the modulated
information is transmitted in a bandwith considerably
greater than the frequency content of the original information.
STORE AND FORWARD - A mechanism that allows messages to be stored at some
point in a network when a complete
transmission path to the receiving terminal is not available and then retransmits them when
a transmission line becomes free.
SUBCARRIER - A carrier that is applied as modulation on another carrier or on an
intermediate subcarrier.
SUBSCRIBER NUMBER - Part of the national numbering plan, the subscriber number is
the last four digits of a telephone
number.
SWITCH - A piece of equipment that establishes and routes communication paths
between separate extensions.
SYNCHRONIZATION - Process of adjusting a receiving terminal's clock to match the
transmitting terminal's clock.
SYNCHRONOUS - In step. A form of transmission that uses no redundant information (such as the start and stop bits in asynchronous transmission) to identify the beginnings and ends of characters. The timing base is supplied by sync characters transmitted prior to data; usually, synchronization can be achieved in two or three character times. T-CARRIER OR T1 CIRCUIT - Specialized circuit developed in the 1960's for the
transmission of digital signals over the
telephone network. These circuits transmit approximately 1.5 million bps and can carry up
to 24 voice channels.
TELECOMMUNICATIONS - Any communication process that allows the transmission
of information from a sender to a receiver
by means of an electromagnetic or lightwave medium.
TELEPHONE - A piece of equipment used for the general transmission of voice
communications.
TELEPHONY - System of speech telecommunications.
TELETEX - Service enabling document correspondence on an automatic memory-to-memory basis over telecommunications
networks. Intended to be complementary to and to interwork with telex and data
communications services. Information is transmitted
in page format to be either displayed on a video display unit or used to produce hard copy.
TELETEXT - Generically, one-way transmission designed for widespread broadcasting of
graphics and textual information, for
display on subscriber televisions or low-cost terminals.
TELOCATOR ALPHANUMERIC PROTOCOL (TAP) - The precursor to TDP which is
a simple protocol dedicated to the
forwarding of alphanumeric pages. Although the features and capabilties of TAP are
included in TDP, the TAP protocol may coexist
with TDP. TAP is used to forward binary data to RF linked computers, if input is
formatted and processed as described in the
document referred to as the Telocator Format Conversion Process.
TELOCATOR CONVERSION PROCESSOR - The front-end processor which executes
the Telocator Format Conversion
process.
TELOCATOR DATA PROTOCOL (TDP) - This is the entire suite of protocols which
together define the flow of messages from
input devices through several processing steps until the entire message is received by an
RF linked computer. The suite is comprised
of several protocols: Telocator Message Entry (TME), Telocator Radio Transport
Protocol (TRT), and Telocator Mobile Computer
Protocol(TMC).
TELOCATOR FORMAT CONVERSION - The document which describes how binary
data messages may be forwarded to RF
linked computers through the use of the TAP protocol.
TELOCATOR MOBILE COMPUTER PROTOCOL - The protocol which operates
between the RF receiver and the mobile
computer which is the ultimate recipient of the data sent from the MED.
TELOCATOR NETWORK PAGING PROTOCOL (TNPP) - Signaling protocol
developed and supported by Telocator that
supports interconnection of terminals from different manufacturers into wide-area paging
systems.
TELOCATOR RADIO TRANSPORT PROTOCOL - Describes the format of data which
is forwarded to RF receivers.
TIME DIVISION MULTIPLEXING - A method of combining several communications
channels into a single circuit by dividing
the transmission path into a number of discrete time slots and assigning each channel its
own intermittently repeated slot.
TIME-DIVISION MULTIPLEXING - Switching method for time division multiplexing
signal which requires shifting from one slot
to another in the frame.
TONE - A type of telephone dialing that sends to the central office a unique acoustic
sound for each number pressed on the dial pad.
TOUCH TONE - AT&T's registered trademark for pushbutton (DTMF) dialing.
TRAFFIC - The volume and intensity of transmitted signals on a communications channel.
TRANSDUCER - Apparatus that converts signal form.
TRANSMISSION - The sending and receiving of telecommunications messages through
appropriate channels.
TRUNK - A communications channel linking a central office with a PBX or other
switching equipment.
TRUNK CARDS - Integrated circuit boards that provide physical termination points for outside trunks. USER - Subsciber who partakes of a particular telecommunications procedure or service. VENDOR - Seller of telecommunications services or equipment.
VOICE PAGING ACCESS - Allows attendants and station users the ability to have dial
access to customer-provided loudspeaker
paging equipment.
VOICE-MAIL - Sophisticated telephone voice messages that are recorded and translated into digital bits for storage and manipulation. Voice-mail systems use specialized hardware and software and can be incorporated into a PBX or uses as a stand-alone system. WAIVERS- Term commonly used to refer to requests made by the BOC's and AT&T for
modifications of the Computer II and
MFJ plans.
WIDEBAND- A communications channel with a bandwidth wider than a voice grade
channel, usually 56 bps or greater.
WIRELESS MESSAGE FORMAT - Format used in which binary data and control information to be sent to a remote device is encoded by the application at the MED. |
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