ICAO selective calling was initially defined in 1985 using twelve tones (Tones "A" to "M", but without tone "I"). In 1994 the ICAO calling system, also known as ANNEX10, was extended with the additional tones "P", "Q", "R" and "S" and now operates with 16 tones.
|
Parameter |
Value |
|
Frequency range |
HF |
|
Operation modes |
Analogue Selcal |
|
Symbol rate |
1000 ms |
|
Modulation |
USB |
|
Receiver settings |
USB |
|
Input format(s) |
AF, IF |
The allocation of selective call addresses is exclusively managed by Aeronautical Radio, Inc. ARINC (ICAO Designator Selcal Registry).
Each address consists of two pairs of tones, e.g., "AB-CD". Both pairs have a duration of 1,000 ms. Between each pair an interval of 200 ms is inserted. ICAO Selcal is used on all frequency bands (HF and VHF/UHF).
ICAO Selcal Tone Allocation
|
Designation |
Frequency (Hz) |
Designation |
Frequency (Hz) |
|
RED "A" |
312.6 |
RED "J" |
716.1 |
|
RED "B" |
346.7 |
RED "K" |
794.3 |
|
RED "C" |
384.6 |
RED "L" |
881.0 |
|
RED "D" |
426.6 |
RED "M" |
977.2 |
|
RED "E" |
473.2 |
RED "P" |
1083.9 |
|
RED "F" |
524.8 |
RED "Q" |
1202.3 |
|
RED "G" |
582.1 |
RED "R" |
1333.5 |
|
RED "H" |
645.7 |
RED "S" |
1479.1 |