Realistic (?): Strange "low tone beep".

Feed provided by Broadcastify on Scanner Radio app. Also, using an Uniden BC245XLT to receive 464.50Mhz, and a security alarm company apparently during routine maintenance of a local fire alarm. I saw no smoke on the horizon so, naturally I presume maintenance.

This is only in regards to the strange "low tone beep" on the scanner feed, one of which I've never heard before today. I had to check everything in the shack to be sure it was none of my own equipment. There's data noise in the background. That's routine, being so close to downtown. Just the tone on RFD. There's been various routine page outs for persons down. I just don't know. It's erratic. Maybe it's a timed code?