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. CCIR (Consultative Committee on International Radio) functions have largely been taken over by ITU

Itu

Itu is an old and historic municipality in the state of São Paulo in Brazil. The population in 2009 was 157,384 and the area is 641.68 km². The elevation is 583 m. This place name comes from the Tupi language, meaning big waterfall. Itu is linked with the highway numbered the SP-75 and are flowed...

-R.
One common type of CCIR selcall used in VHF and UHF FM

Frequency modulation

In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 two-way radio

Two-way radio

A two-way radio is a radio that can both transmit and receive , unlike a broadcast receiver which only receives content. The term refers to a personal radio transceiver that allows the operator to have a two-way conversation with other similar radios operating on the same radio frequency...

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

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

Millisecond

A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....

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

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