OpenTX - Application Note 31
Throttle Setting Announcement
Announce the value of the throttle only when the throttle changes.
Here is feature to use when you wish to know what the throttle setting is more accurately than just feeling the position of the stick. It is achieved with one logical switch and one special function.
The following logical switch LS1 is on when the throttle stick changes by more than 1 unit.
Special function SF1 plays the value of the throttle once when LS1 turns off, that is when the throttle stops changing.
Note that the throttle value range is -100 to +100 with 0 in the centre.