CCIR (selcall)

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There are many types and formats of CCIR Selcall. For example, CCIR 493-4 is a standard format for HF Selcall for Land Mobile applications. [1] CCIR (Consultative Committee on International Radio) functions have largely been taken over by ITU-R. One common type of CCIR selcall used in VHF and UHF FM two-way radio communications, is a 5-tone selective calling system mainly found in some European countries and used by the Swedish Police and the Turkish Police.

Frequency modulation encoding of information in a carrier wave by varying the instantaneous frequency of the wave

In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave.

Two-way radio a radio that can do both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content; allows the operator to have a conversation with other similar radios operating on the same radio frequency (channel)

A two-way radio is a radio that can both transmit and receive a signal, unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver designed for bidirectional person-to-person voice communication with other users with similar radios using the same radio frequency (channel). Two-way radios are available in mobile, stationary base and hand-held portable configurations. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds.

The tone duration of a 5 tone CCIR selcall is 100 milliseconds (± 10 ms) and the tones are transmitted sequentially.

A millisecond is a thousandth of a second.

CCIR tone frequencies
Value Frequency
1 1124 Hz
2 1197 Hz
3 1275 Hz
4 1358 Hz
5 1446 Hz
6 1540 Hz
7 1640 Hz
8 1747 Hz
9 1860 Hz
0 1981 Hz
Group (A) 2400 Hz
Repeat (E) 2110 Hz

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References

  1. "Selcall". CCIR.