RadioReference.com Forums

I have noticed that many transmissions from units on the local fire department convectional repeater end with a short "beep," as shown in the video clip linked below. I do not notice this on the Sheriff or EMS repeater. I seem to vaguely remember reading an explanation about this behavior many years ago, but I was unable to find anything in the forums that aligned with what I am hearing. Does anyone know what causes this tone?

Thanks!