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A plain-language radio check is the means of requesting and giving a signal strength and readability report for radiotelephony (voice) communications, and is the direct equivalent to the QSA and QRK code used to give the same report in radiotelegraph communications.
Radiotelephony procedure (also on-air protocol and voice procedure) includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the armed forces, in civil aviation, police and fire dispatching systems, citizens' band radio (CB), and amateur radio. Voice procedure communications are ...
A typical lineman's handset integrates an earpiece, a mouthpiece, a dialing interface, and a set of test leads for connecting to the telephone circuit. Originally, lineman's handsets featured a rotary dial , but modern sets use some variant of the standard 12-button DTMF keypad and also employ an amplifier for speaker use.
Some radio users have inappropriately started using the Circuit Merit telephone line quality measurement. [ citation needed ] This format is unsuitable for radiotelegraph or radio-telephony use because it focuses on voice-to-noise ratios, for judging whether a particular telephone line is suitable for commercial (paying customer) use, and does ...
Morse code is called the original digital mode. Radio telegraphy, designed for machine-to-machine communication is the direct on / off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying or ASK, may be considered to be an amplitude modulated mode of communications, and is rightfully considered the first digital data mode.
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time ...
The development of the APCO Ten Signals began in 1937 [5] to reduce use of speech on the radio at a time when police radio channels were limited. Credit for inventing the codes goes to Charles "Charlie" Hopper, communications director for the Illinois State Police , District 10 in Pesotum, Illinois .
Since radio circuits inherently possess a broadcast network topology (i.e., many or all nodes are connected to the network simultaneously), one of the first technical challenges faced in the implementation of packet radio networks was a means to control access to a shared communication channel to avoid collisions of signals.