Unknown identifier for a couple of milliseconds at the end of the transfer.

[slavikby]

Hello ! At the end of the transmission, it was noticed that the station was transmitting an unknown signal in just a few milliseconds. (All possible signals in the Menu are disabled!!!). In frequency modulation it is not noticeable by ear; the fact of transmission was noticed when listening to one’s own signal on the air simultaneously with a weak signal from another station. This is not a tone, not a DTMF signal.
Do you have any information? Thank you !