From The RadioReference Wiki
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-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.
The tone duration of a 5 tone CCIR selcall is 100 milliseconds (± 10 ms) and the tones are transmitted sequentially.
|Group (A)||2400 Hz|
|Repeat (E)||2110 Hz|