chapter  5
3 SELCAL
Pages 4

SSB because there is no transmitted carrier to

indicate that a signal is present on the channel.

The aircraft SELCAL system is defined in

Annex 10 to the Convention on International

Civil Aviation (ICAO), Volume 1, 4th edition of

1985 (amended 1987). The system involves the

transmission of a short burst of audio tones.