Glossary | Business Communications

Two-Way Radio Support


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This combines the 10BASE-T and 100BASE-TX Ethernet standards into a single term. 100BASE-TX is a general term referring to a group of fast Ethernet standards used for transmission over twisted-pair cables, etc. 10BASE-T is another Ethernet standard. Both 10BASE-T and 100BASE-TX are used to link equipment in a star-configured LAN via a hub. 10BASE-T can be used to transmit data at up to 10Mbps over a maximum distance of 100 meters, while 100BASE-TX is capable of data transmission at 100Mbps over the same distance. 100BASE-TX equipment is usually compatible with 10BASE-T, so it is possible for them to coexist on a single network.

2-Tone / 5-Tone Signalling

Type of signalling used to enable alerts, alarms, send IDs, and many other functions. This refers to two-tone squelch, a function which employs a sequential transmission of 2 audible tones for user selection, enabling the receiver to hear an alert tone. It can also be used for group calling.

4-Level FSK modulation

Frequency Shift Keying (FSK) is a modulation method by which the instantaneous frequency of a carrier is discretely changed according to a digital code.

5-Tone (Five-Tone)

Originally a European signalling protocol, this is a burst of audio tones (actually as many as 7) used to initiate a radio conversation via selective calling. Several formats are used.


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ANI (also known as PTT ID)

Stands for Automatic Number Identification. The radio will automatically send unit ID information that identifies the caller to everyone receiving the call.

Audio Output – Louder

Standard radios transmit audio at around 400-500mW. Enhanced or Louder Audio Output ranges from 700mW to 1000mW. These radios are particularly good for noisy environments (construction, conventions, manufacturing, concerts, clubs, etc.)

Auto Dial (also known as Speed Dial, or DTMF Auto Dial)

A memory function that allows phone numbers to be stored and recalled with a push of a button.


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Base Station

A Transmitter / Receiver sited in a fixed location


Battery Options:

- Lithium ion (Li-ion)
This is the battery technology used in most mobile phones. Li-ion batteries hold more energy than other batteries of the same weight. They do not suffer from the memory effect that can damage other batteries if charged incorrectly.

- NiCad (Nickel Cadmium)

- NiMH (Nickel Metal Hydride)

Busy Channel Lock-Out (BCLO)

This feature prohibits transmission if a channel is in use. It also keeps users from monitoring people with different privacy codes.

Busy Tone Lock-Out (BTLO)

Sends a ‘busy’ signal to someone trying to transmit over a channel in use (used with Busy Channel Lockout function).


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Channel Aliasing

Allows the user to give each channel a user defined name.

Channel Announce

A radio with this feature will clearly speak the channel description when changing channels, convenient when a worker needs to stay focused on the task they are doing.


Quickly copy the settings from one radio to another, or from a PC to a radio. Makes set-up of multiple radios much easier.

Community Repeater

A repeater base station which is shared by several separate user groups

Compander (or X-Pand voice compression)

Technology that improves audio clarity and reduces 'hissing' in narrowband signals.

Courtesy Beep

Signifies when a person is through talking.

CTCSS / DCS Encode / Decode

Continuous Tone Controlled Squelch System. CTCSS codes are sometimes referred to as ‘privacy codes’ as they allow several groups of radio users to make use of the same channel without overhearing the other groups.


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Stands for Dual Tone Multi Frequency and the generic term most people know is 'Touch Tone'. It is the tone generated when keys are pushed on a telephone. In two-way radios these tones can be used to dial phone numbers or to send codes to activate functions. Some of the more common DTMF functions used in two way radios are: DTMF ANI (Automatic number identification - ANI), which transmits an individual ID code with every press, or release of the PTT, that identifies a specific user to the dispatcher; DTMF Paging which allows the radio to receive pager messages; DTMF Selective Call, this silences transmissions not intended for a specific unit, eliminating all non-directed chatter on the air; DTMF Speed Dial (or Auto Dial), a shortcut to a pre-set number. It is designed to speed up dialling numbers repeatedly used or hard to remember. Example: A user configures B5 with key type ‘Speed Dial’ and ‘number’, each time B5 is pressed it dials the number automatically.


Simultaneous two-way sending and receiving


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Effective Radiated Power

Electronic Serial Number (ESN)

A serial number that is embedded in the electronics of the radio and can be read by other equipment for easy identification of the user.

Emergency Mode

Sends an alert to co-workers or a dispatcher. It also activates the microphone so they can listen to the audio transmission.

Encryption (also know as Voice Scramble)

A technology is used to scramble communications to prevent other radio users in the vicinity from listening to your conversations.
•Voice Inversion Encryption is a simpler type of Voice Scrambler used to jumble communications to prevent other radio users in the vicinity from listening to your conversations.
•Rolling Code Encryption, a feature usually only available on higher-end units, is a more robust technology of encoding that is not as easily decoded as scrambling.
•DES 20 provides protection against more advanced types of listening technologies.
•Digital DES P25 secure 56 bit encryption (for public safety applications and surveillance).
•Digital AES P25 provides the maximum security with 256 bit encryption (for public safety applications, surveillance, and military applications).


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Frequency Modulation


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GPS (Global Positioning System)

Some radios come with an integrated GPS. This can be very useful if you are planning on taking a hike with your radio or going into unfamiliar areas.

Groups (also known as Zones)

Radios with many channels break the channels up into sets called Zones or Groups. On most radios there are 16 channels in each group.


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Became a trademark of Motorola for a hand portable radio in 1951

Hz (Hertz)

1 cycle per second


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Intrinsically Safe (IS) (also known as FM Approved)

Intrinsic safety (IS) is a technology for safe operation of electronic equipment in locations where explosive gases may be present. Intrinsically safe radios are designed so the electrical energy in the radio is low enough that ignition of the explosive gases will not occur. Manufacturers must meet specific standards in order for a product to be certified as 'Intrinsically Safe'. Radios meeting this standard have the designation 'Intrinsically Safe' or 'FM Approved' on their documentation.

IP Rating (Ingress Protection)

A standard for rating the protection level against foreign objects (such as dust) and water. The first number represents the level of protection for objects (0=none, to 6=complete). The second number represents the level of protection against water (0=none, 8=complete).


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KHz (Kilohertz)

1,000 cycles per second


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Lone Worker

A safety feature that is available on some radios for those who work alone. At pre-set intervals the lone worker will receive an audible alert from his radio to press a button. By pushing the button he is letting his control centre know that he is ok. However should the user continue to ignore the audible alerts then the radio will go into Emergency Mode and alert the control centre accordingly.

Low Battery Alert

An alert sounds or indicator light flashes when battery gets low. Some radios have 2 levels of alert.


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Manned Based Unit

Desk mounted radio with power supply and fist or desktop microphone


This is a safety feature available on some radios. A tilt-switch within the radio automatically sends an alarm signal when the radio is tipped on its side for longer than the pre-set period. However the radio will first bleep to alert the user that the alarm signal will be sent if the radio is not repositioned upright. This feature alerts the other radio users to the possibly that the lone worker may have been, for example, overcome by a sudden illness or attacked.

MHz (Megahertz)

1,000,000 cycles per second

Military Specification Standards (MIL-STD 810)

This certifies that a radio meets certain U.S. Department of Defence standards for ruggedness. If a radio is certified to MIL-STD 810 E or F you can be sure that it will withstand the toughest physical conditions (i.e. vibration, shock, rain, dust, temperature, etc.). Some radios meet only part of the 24 categories for this ruggedness standard. If you want to review the ruggedness rating for a particular radio look at the spec sheet for that radio model, it will include the MIL-STD tests that the radio passed.

Mobile Radio

Radio installed in a vehicle


Allows you to check for traffic on a channel before you transmit.


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Office of Communications

Government organisation responsible for controlling and licensing the use of the airwaves.

Out of Range Alert

This feature sends an alert any time you, or one of your party, wanders out of communication range. i.e. known as ARTS™ on Vertex radios


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Stands for 'Project 25'. Is a set of technology standards designed to allow communication between public safety agencies (such as police and fire departments). Developed in response to a lack of communication between different agencies in crisis situations. These radios are not for businesses or personal use.


This is a UK & European standard for basic, short-range radio that can be sold and used by anyone without the need of a radio license. The radios use the same eight frequencies in the UHF band, around 446MHz, hence the name. The radios can have a maximum power output of 0.5 watts.


Private Mobile Radio or Professional / Personal Mobile Radio

Programmable Buttons

Most business grade radios have between 2 and 9 programmable buttons. Many of the listed features of a radio can be used only if they are programmed into one of these buttons, and accessed by pressing one of these buttons.

PTT pr Press-To-Talk or Push-To-Talk

This is the button on the radio that is held down to make the radio transmit and then released to receive.


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See 'CTCSS/DCS' or 'Privacy Codes'.


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Repeater Base Unit

Unmanned fixed base unit with external antenna providing enhanced site coverage

Relay Delay

When using a repeater, keeps the repeater transmitter open a short time after a radio user releases the PTT switch. This allows a user group to conduct a normal conversation without delays from re-activating the repeater. This "polite pause" can be set from 0-7 seconds.

Remote Listen (also called Emergency Mic Monitoring or 'Hot Mic")

A safety feature which turns on the radio remotely so a dispatcher can listen to what is happening near the radio. Commonly used in public safety, security, and applications where workers may be working alone.


Radio Frequency




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Most radios today have a scanning feature and all business grade radios have a scanning feature. Scanning does what the name implies, it scans for traffic on the channels you designate. Once it detects a transmission it stops so that you can hear the transmission. You can select multiple channels you wish to ‘scan’ for communications, the radio will only pick up communications on those channels you selected. This can be a handy feature if you have multiple groups assigned to each channel, you can use a separate ‘broadcast’ channel to relay messages to everyone. Each group can set their radio to scan both their group’s channel and the ‘broadcast’ channel. Or, maybe you have two groups who need to hear each other’s communications at times. When they need to hear each other, all they do is set their radio to scan both channels.

Scrambling (also known as Encryption)

See ‘Encryption’ for a description.


Selective Calling

Semi-Duplex or Half Duplex

This is when you can send and receive, but only one-way at a time, as with a two-way radio. The radio user is unable to interrupt the calling party and must wait until they finish before they can reply


A one-way communications channel as used in paging systems


Sequential Tone Signalling


Electronic circuitry that mutes the radio speaker and controls the hissing ‘white noise’. Basically, this is a control that cuts off the speaker or headphone when no signal is present, keeping you from hearing the ‘hiss and crackle’. 'Raising the squelch' will raise the threshold at which you receive communications. This may be necessary if you are receiving unwanted messages from other people using the same channel in your vicinity.


See IP Rating

Surveillance Mode

Disables the radio's lights and beeps.


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Talk-through Repeater

See 'Repeater Base Unit'

Talk Around

When using a repeater, this feature circumvents the repeater to talk directly to another radio that is close by, to reduce unnecessary airtime through the repeater system.


Terrestrial Trunked Radio


A radio with this feature can also send and receive text messages, much like a smart phone.

Time Out Timer (TOT)

TOT is a timer that shuts off the radio's transmission. Since most transmissions average 3-4 seconds in duration, a longer single transmission usually indicates an inadvertent mistake, or there's a lengthy conversation going on that needs to be curtailed. This reduces the chances of busy channels, unnecessary chatter, and dead batteries.


A radio that transmits and receives, the term being created by combining the words ‘transmitter’ and ‘receiver’

Transmit Inhibit

Prevents transmission on a channel, basically making it a 'receive only' channel.


In conventional radios a frequency is assigned to a channel through programming, one frequency per channel. Channel assignments in a conventional radio can only be changed by re-programming the channel. In a Trunked radio system all frequencies are in a 'pool', the pool is managed by another device. Frequencies are allocated to a radio's channel dynamically as they are needed. Once the transmission is complete the frequency is released back into the 'pool'. This is a much more efficient use of frequencies but requires more sophisticated equipment.

Two Way Radio

A term used for any radio that transmits and receives




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Ultra High Frequency (400 – 470 MHz) for business radios

User Set Mode

Allows the user to change some pre-programmed settings.


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Very High Frequency (136 – 174MHz) for business radios

VOX (Voice Operated Switch)

This feature is a must-have for anyone who will be busy with their hands while talking. Most business grade radios include this feature, however, you must have a hands-free headset to use it. The VOX feature sends the unit into transmit mode automatically when it detects speech in the direction of the microphone. Some microphone models offer both VOX and PTT options.


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Walkie Talkie

Is another reference for Two-Way Radio although the original name referred to a back pack radio.


See IP Rating.

Weather Channel Alerts

This feature will give you the latest NOAA (National Oceanic Atmospheric Association) weather information delivered to your radio real-time. This feature is more common in higher-end aviation, and marine radios.

Whisper Mode

Reduces the audio volume for use in quite areas (i.e. school classrooms, libraries, courtrooms, etc.).


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X-Pand Voice Compression

See ‘Compander’ definition.


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Zones (also known as Groups)

Radios with many channels break the channels up into sets called Zones or Groups. Usually there are 16 channels in each group.