What are methods of signalling as per INTERCO or International Code of Signal ?

1. A dot is taken as the unit;
2. A dash is equivalent to three units;
3. The space of time between any two elements of a symbol is equivalent to one unit; between two complete symbols it is equivalent to three units; and between two words or groups it is equivalent to seven units.

Voice over a loud hailer

Whenever possible plain language should be used but where a language difficulty exists groups from the International Code of Signals could be transmitted using the phonetic spelling tables.

Radiotelegraphy and radiotelephony

When radiotelegraphy or radiotelephony is used for the transmission of signals, operators should comply with the Radio Regulations of the International Telecommunication Union then in force.