Controller beeping

[Marc70]

First time I'd disconnected the Phantom, but forgot to turn off the controller (is this also referred to as TX?) several minutes went by before the steady beeping started.
After that, I used it several times with no issues, but then it would beep ( long steady) as soon as I turned it on. I shut it off, then on and it's gone.
I checked my batteries, and their good.
Can't find anything about this anywhere, was hoping someone here would know.

 

[reALIGNed]

I think its a beep tone to remind you that the tx is still "on", so its not left this way to drain your batteries. And yes, "tx" is an abbreviation for transmitter, and "rx" is the receiver.