Two-way Radio Glossary

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1..9

1G - First generation technology, such as analog cellular.

2x2 Paging - (see 2-tone Paging)

2-tone Paging - Two-tone sequential tone calling format, such as Motorola Quck-Call™, GE Type 99 or Plectron.

3G "Third-generation" type PCS/cellular services and technology. Includes high-speed internet, video and conferencing.

5/6 Tone - Sequential tone formats used for paging, selective calling and ANI. Variations include from 3 to 8 tones in squence, usually no longer than 100mS in duration, sometimes with a preamble tone.

AF - (see Audio Frequency)

AFSK - Audio Frequency Shift Keying. The use of an audio frequency signal to transmit data or digital modulation, such as digital ANI or packet signals.

AM - Amplitude Modulation. Considered the most basic form of modulation, the magnitude of a carrier signal is controlled by the voice or analog intelligence to be transmitted.

Amplitude Modulation - (see AM)

AMPS - Advanced Mobile Phone System. The original cellular type mobile phone service to be deployed in the US in the early 80's, invented by Bell Labs.

analog signals - DC, tone, or audio signals - voice or tone signals. (see also digital signals)

ANI - Automatic Number Identification. A coded signal used to identify a transmitter or unit number. Usually heard as a short burst at the beginning or end of each transmission. May also be used to indicate "Duress" or "Man down," or vehicle location. Analog or digital signaling. (see also Digital ANI)

Automatic Number Identification - (see ANI)

Audio frequency - Signals used for modulation, in the range of 20Hz to 20KHz. For two-way radio, typical range is 300Hz to 3KHz for voice.

Auto-patch - A device which interfaces a radio to a telephone line, typically controlled by DTMF codes.

Base [station] - Radio equipment installed in a building or other fixed location. May be a mobile unit with external power supply, or AC-powered equipment, controlled directly or remotely, such as a tone-remote console.

Burst [tone] - A single, short tone sent at the beginning of a radio transmission to open squelch on a repeater or control other functions.

Carrier - A radio-frequency signal intended to carry intelligence (modulation).

CCIR - Comite Consultatif International de Radio, sets certain international formats and standards.

Central Processing Unit - (see CPU)

CEPT - The European Conference of Postal and Telecommunications Administrations

Continuous Tone Coded Squelch System - (see CTCSS)

CPU - Central Processing Unit. A computer chip, or microprocessor circuit, often found in modern communications equipment.

CRC - Cyclic Redundancy Check. Error checking; A method of testing the validity of a received set of data, such as packet.

CTCSS - Continuous Tone Coded Squelch System. A "sub-audible" tone, usually below 300Hz is transmitted in order to open the squelch for a receiver or repeater operation. Used to reduce interference or to separate different users on the same frequency.

dB - (see Decibel)

DC remote - Remote control of radio equipment via multiple direct-current levels, usually over a single pair of conductors. (see also tone-remote)

DCS - (see Digital Code Squelch)

Decibel - (deci-Bel) A measurement of power ratio, expressed in "dB." Calculated as 10·log(P1/P2) for power, or 20·log(V1/V2) for voltage ratios.

Digital Code Squelch - Functions the same as CTCSS, but uses a 3-digit octal code [000~777], sent as a binary encoded 23-bit word at 134.3 baud.

Digital ANI - A digital ANI signal, using a short burst of digitally encoded FSK or AFSK data at the beginning or end of a transmission. Formats include Motorola MDC-1200™, GE-Star™, and others.

Digital PL™ - Motorola (see Digital Code Squelch)

digital modulation - The conversion of analog signals or other information into a numeric format for transmission over radio. Used for security and/or efficiency, or to send data over radio.

digital signal - A numeric representation of speech, codes or other information which has been digitized for security or efficiency.

DPL - Digital PL™ (see Digital Code Squelch)

DTMF - Dual-Tone Multi-Frequncy aka Touch-Tone™. A standard set of 8 tones, used for paging, ANI, remote control or interconnect applications.

EEA - Electronic Engineering Association - United Kingdom

EIA - Electronics Industry Association, sets many of the standards used in land mobile radio systems.

Eurosignal - A 6-tone AM paging format used in CEPT countries.

ETSI - European Telecommunications Standards Institute

ERP - Effective Radiated Power

FIFO - First-In, First-Out. Indicates data handling of a sequential buffer or system.

FILO - First-In, Last-Out. Indicates data handling of a sequential buffer or system.

FM - Frequency Modulation. The frequency of a carrier signal is varied by the voice or intelligence signal to be transmitted.

Frequency Shift Keying - (see FSK)

Frequency Modulation - (see FM)

Frequency synthesizer - A programmable VFO circuit which is capable of producing a range of frequencies, usually controlled by a CPU or user input.

FSK - Frequency Shift Keying. Digital modulation of a carrier by means of directly shifting the VCO frequency.

Gap - The space between sequential tones in certain formats.

Group - Group calling; A set of users which can be directly addressed via selective calling or paging.

HSC - Hexidecimal Sequential Code. A 5/6-tone signaling format, used in some public service and private systems for selective calling or paging.

Hz - Hertz; a measurement of frequency expressed in cycles per second.

Interconnect - Refers to interface or connection between a radio system and telephone line. Applications include auto-patch, SMR, radiotelephones, PCS, GSM, cellular networks. May also refer to a service provider.

IMD Intermodulation Distortion

Intermod (see Intermodulation)

Intermodulation

Jin-pole - A hook-shpaed pipe with a pulley, when attached to a radio tower is used to hoist heavy equipment, antennas, feedlines, or tower sections during assembly.

Kc - Kilo-cycles (see KHz)

KHz - KiloHertz; Frequency (times) 1000 Hertz. Example: 3.3 KHz = 3,300 Hz

Knox Box™ - A key safe intended for fire department emergency building access, operated by transmitting a code via the Knox Company's proprietary DTMF format.

Ku [band] - A range of microwave frequencies used for satellite broadcasting. 11.7 ~ 12.2 GHz.

LF - Low Frequency

LNA - Low Noise Amplifier; An RF amplifier used for microwave reception, usually mounted at the feedpoint. (see LNB)

LNB - Low Noise Block down-converter; Replaced LNA's used in older satellite & microwave systems, amplifies signal and down-converts signal to a lower intermediate frequency in order to reduce feedline losses.

LPF - Low Pass Filter; a filter used to block high frequencies, either radio or audio.

MODAT - 7-tone ANI and status system by Motorola

modulation - any of the methods used to superimpose intelligence onto a radio signal, or "carrier" signal. Types include AM, FM, SSB, et al.

NATEL - Scandanavian National Telephone

NRZ - Non Return to Zero. Indicates a type of signal which has a (+) positive state and a (-) negative state, but no zero-state.

OCF - Off-Center Feed; Refers to the feedpoint of a microwave dish not being centered. Allows for lower tilt-angles of small dish antennas.

PL Tone - Motorola (see CTCSS)

Plectron - A set of audio tones used in 2-tone or 5/6-tone selective calling, paging or ANI.

PLL - Phased Locked Loop. A self-correcting feedback circuit used in VFO's or frequency synthesizers to provide a stable radio frequency source for receivers and transmitters.

Phased Locked Loop - (see PLL)

Preamble - A long tone or code preceding a page or selective call. Used for group calling or as a "wake-up" code.

Private Line - Motorola (see CTCSS)

Q - Quality rating of tuned electronic circuits, bandwidth or selectivity.

Q-signals - Originally developed for telegraphy, then amateur radio use. A 3-letter code meant to shorten transmission times of frequently used information. Like 10-codes. Example: QTH = location.

Radio Frequency - Refers to the typical range of frequencies used for carrier signals in radio equipment.

REACT - Radio Emergency Associated Communication Teams, a volunteer public service organization, usually of amateur or GMRS operators.

RF - (see Radio Frequency)

RFI - Radio Frequency Interference

SECODE - Similar to pulse telephone dialing, a two-tone format typically used by EMS departments to alert hospitals of incoming patients.

SSB - Single Sideband, a type of AM modulation, where the carrier frequency and upper or lower sideband are suppressed.

Sideband -

SelCall - (see Selective Calling)

Selective calling - The use of a coded signal or ANI to direct a radio transmission to a single user or group of users.

Sub-audible [tone] - A very low frequency audio tone of the type used for CTCSS or DCS signaling, usually filtered out by the speaker amplifier.

T/R - Transmit/Receive. Usually in refers to a relay or other electronic device used to switch antennas or radios between transmit and receive modes.

Tone-remote - The use of special audio tones to activate remotely installed radio equipment. May be connected by twisted-pair or radio link.

TR - "Tip and Ring" - An old term which refers to the two conductors of a telephone circuit or twisted pair line.

UHF - Ultra High Frequency, frequencies in the range of 300MHz to 3GHz.

USB - Upper Sideband (see SSB)

UTP - Un-shielded Twisted Pair; such as telephone or data cable, CAT3, CAT5, etc.

Variable Frequency Oscillator - (see VFO)

Voltage Controlled Oscillator - (see VCO)

VCO - Voltage Controlled Oscillator. A radio frequency oscillator used in receivers and transmitters, usually tuned by applying a variable voltage to a varactor diode in a PLL or frequency synthesizer.

VFO - Variable Frequency Oscillator. The radio frequency oscillator in a receiver or transmitter used to generate the fundamental carrier frequency.

Wake-up - A tone or code signal used to bring a pager or receiver out of "sleep" or power saving mode.

X band - Refers to the 10~11GHz frequency range.

ZVEI - Zentralverband Elektrotechnik, Germany

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