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Glossary of radio expressions

ARQ   Automatic repeat request
Error-control method for data transmission that uses acknowledgements and timeouts to achieve a reliable data transmission over an unreliable medium. Also known as Automatic Repeat Query.  Wikipedia
ASCII   American Standard Code for Information Interchange
Character encoding scheme, based on the ordering of the English alphabet, using 7-bits to describe each letter. Commonly used to represent text in computers, communication equipment and other devices that use text. Most modern encoding schemes are based on extended ASCII.  More  Wikipedia
BAUDOT   Method for sending text-based messages over wire or radio links, using a 5-bit digital code. Based on the ITA2 standard. Also known as Baudot-Murray code and as CCITT-2.  More  Wikipedia
CEOI   Communications-Electronics Operating Instructions
CIA   Central Intelligence Agency
 Wikipedia  Website
CNR   Combat Net Radio
COMSEC   Communications Security
Covert Operation   General term for a 'clandestine operation' legally carried by, or on behalf of, a government body. In the US, covert operations are typically carried out by the CIA. The expression 'covert' is sometime expanded to include secret service work, VIP protection, surveillance and eavesdropping.
DELTACS   Army Corps Tactical Area Communications System
Mobile tactical area communications system providing secure, digital communications for army corps size military units. Jointly developed by Hollandse Signaalapparaten (HSA) in Huizen (Netherlands) and GTE Government Systems Corporation in Massachusetts (USA). The Dutch military communications system ZODIAC was based on DELTACS.
DF   Direction Finding
When a radio transmitter is on the air for a sufficiently long period of time, it is possible to determine the direction of the transmitter. This is often done by using directional antennas and plotting the angle from two or three intercept stations on a map. It is also possible to a doppler antenna for mobile searches and to use a simple field-streng indicator to find nearby transmitters.
ECM   Electronic Counter Measures
Common name for measures taken against an adversary's communications, such as eavesdropping, interception and direction finding.
ECCM   Electronic Counter Counter Measures
Equipment used in secure communications (COMSEC) to protect against counter measures, such as eavesdropping, interception and direction finding. Frequency Hopping (FH) and encryption (CRYPTO) are examples of ECCM.
EMU   Electronic Message Unit
EPM   Electronic Protection Methods
Expression - frequently used by Thales - for a radio channel that has been secured by means of electronic measures, like encryption (CRYPTO) and/or frequency hopping (FH). Also known as ECCM.
ETSI   European Telecommunications Standards Institute
FEC   Forward error correction
A technique for controlling (and correcting) errors in data transmission over an unreliable or noisy medium, such as an HF radio channel.  Wikipedia
FH   Frequency Hopping
Method for quicky changing the frequency (channel) during a transmission in a seemingly random order. This is done as an electronic counter counter measure (ECCM), to protect the conversation against eavesdropping and interception by the enemy. Popular frequency hopping systems are known by the codenames HAVEQUICK, M3TR and JAGUAR.
Fill   Key-fill
Filler   Key fill device
FM   Frequency Modulation
HF   High Frequency
300 kHz - 30 MHz
IDF   Israel Defense Forces
ITA2   International Telegraph Alphabet No. 2
International standard for sending text in digital 5-bit format over teleprinter infrastructure (telex). Also known as CCITT-2 and as Baudot-Murray code.  More
ITA5   International Telegraph Alphabet No. 5
International standard for sending and storing text in digital 7-bit (actually 8-bit) format. Also known as ASCII.  More
Key   A key is a piece of information (parameter) that determines the functional output of a cryptographic algorithm (cipher). Without the key, the algorithm can not be used.  Wikipedia
Key-fill   Loading of a crypto-device with key material. Commonly achieved by using a so-caller key fill device (or: filler) to distribute key material.  More
Key fill device   Device used for the distribution of cryptographic material (keys). The device is loaded by a Key Generator, and can dump its contents to a crypto-device or another key fill device.  More
LSB   Lower Side Band
Morse   Morse Code
Method for (manually) transmitting text based messages, by encoding them into a series of dashes and dots, and sending them by means of sound, light or radio waves. Often used on narrow-band (short wave) radio channels.  More
NATO   North Atlantic Treaty Organization
OSS   Office of Strategic Services
Clandestine US organisation for infiltration and sabotage activities during WWII. The predecessor of the current CIA.
OTAR   Over The Air Rekeying
SF   Special Forces
SC   Single Channel
SINCGARS   Single Ground and Airborne Radio System
Combat Radio Network used by the US Armed Forces and part of NATO.  More
SOE   Special Operations Executive
British Special Forces active in clandestine operations behind enemy lines during WWII.  Wikipedia
SOI   Signals Operating Instructions
SSB   Single Side Band
Modulation method, derived from AM with suppressed carrier and one of the side-bands. The resulting side-band can be either USB or LSB.
TAA   TETRA Authentication Algorithm
Encryption algorithm used for authentication of voice and data traffic on TETRA radio networks.  More
TEA   TETRA Encryption Algorithm
Suite of encryption algorithms used for securing voice and data traffic on TETRA radio networks. Known algorithms are TEA1, TEA2, TEA3 and TEA4.  More
TEMPEST   Codename, referring to (the study of) unwanted compromising emanations. This includes the emission of unintentional and unwanted intelligence-bearing signals. If such signals were intercepted and analysed, they might disclose sensitive information. In cryptography, the interceptor might be able to reconstruct (part of) the plain text.  Wikipedia
TETRA   Terrestrial Trunked Radio
Digital two-way trunked radio network, developed in Europe and standardized by ETSI. Voice and data traffic is secured by means of authentication and encryption algorithms.  More
TITAAN   Theatre Independent Tactical Army and Airforce Network
Codename for the current Dutch military communication system that replaced ZODIAC in the early 2000s.  More
TTY   Teletype
Method for sending written (printed) messages over a wire or radio link, using a 5-bit digital code (mostly BAUDOT).
UHF   Ultra High Frequency
300 MHz - 3 GHZ.
USB   Upper Side Band
VHF   Very High Frequency
30 - 300 MHz.
VINSON   KY-57 Voice Crypto
American Voice Crypto device a.s.a. KY-57 or KY-58. Can be used in combination with VRC radio sets and early SINCGARS radios.
ZODIAC   Zone Digitaal Automatisch Cryptografisch beveiligd
Codename for the integrated communications system that was used by the Dutch Armed Forces between 1979 and the early 2000s. It is based on the DELTACS tactical area communications system.  More
Further information
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Crypto Museum. Last changed: Tuesday, 01 August 2023 - 07:38 CET.
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