There are many types and formats of CCIR Selcall. For example
CCIR 493-4
is a standard format for H
Selcall
for Land Mobile applications. CCIR (Consultative Committee on International Radio) functions have largely been taken over by

ITU The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union ...

-R. One common type of CCIR selcall used in

VHF Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VH ...

and

UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...

two-way radio A two-way radio is a radio that can both transmit and receive radio waves (a transceiver), unlike a radio broadcasting, broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and radio receiver, receive ...

communications, is a 5-tone selective calling system mainly found in some European countries and used by the

Swedish Police The Swedish Police Authority ( sv, Polismyndigheten) is the national police force (''Polisen'') of the Kingdom of Sweden. The first modern police force in Sweden was established in the mid-19th century, and the police remained in effect under lo ...

and the

Turkish Police The General Directorate of Security ( tr, Emniyet Genel Müdürlüğü) or Turkish Police Service ( tr, Türk Polis Teşkilatı) is the national civilian police force responsible for law enforcement of the Republic of Turkey, which is affiliated ...

. The tone duration of a 5 tone CCIR selcall is 100

millisecond A millisecond (from '' milli-'' and second; symbol: ms) is a unit of time in the International System of Units (SI) equal to one thousandth (0.001 or 10−3 or 1/1000) of a second and to 1000 microseconds. A unit of 10 milliseconds may be ca ...

s (± 10 ms) and the tones are transmitted sequentially.

References

* {{refend Radio technology Telephony signals