A tone encoder, this SELCAL program produces SELCAL 12/16/32 tone selected calling tones.
The tones are produced in line with the requirements of ASRI SELCAL, ARINC Characteristic 714-6 Mark 3, ICAO Annex 10 Volume II, and ARINC 714A Mark 4.

Since you will always have it with you, unlike those pricey and limited SELCAL text boxes that are never available when you need them, it might be quite useful to test SELCAL decoders. You can bring it with you anytime, anywhere since you will just need to download the app. You can also modify the settings to your preferred way by going to the SELCAL settings.