A few years ago our county went from each agency dispatch on their own frequency to single toneout channel. To find the new tones for the EMS and FD in town I just set my 436HP to "Tone search" and "Record". To make things easier I also ran "Virtual Control" on Butel ARC536 Pro so I could see the tones on the computer screen and also on the log during playback. It may take a while to identify tones of departments that get only a few calls, but in the end this worked fine for me.