FreePBX & Cisco SPA phones getting random 486 busy signals?


I am having an issue with a Freepbx installation. The initial install was in 5/2015 & has about 20 Cisco SPA504G phones.

My problem is that I am getting a ‘random’ 486 busy message on some of the SPA504G phones. The phones are idle for the most part (it is in a large home) & I believe this is newer behavior. I dont recall this during our original installation.

I have updated firmware on all 20 phones to the latest (7.6.2) and I am running version of Freepbx.

For testing I am dialing 600 (which is the number the incoming route uses to ring about 12 of the phones). When nothing is in use I will use either a softphone (if i am remoted in) or a physical SPA504g phone to dial 600. Sometimes i get busy messages (though no one is on the phone and it is physically hung up) other times those same phones are not busy.

Several phones were so ‘stuck’ on the 486 error message I had to do a factory reset & then reprogram the phones by hand (cut & paste).

Any suggestions or theories as to why it would have been fine & now its not? All phones are connected to a 24 port POE cisco switch.


My 7970 stopped working a couple of weeks ago. The lights would light and it would appear to be working, but it would never ring and as soon as someone picked up the receiver, the phone would restart. It was the POE injector going bad. While they aren’t exactly the same symptoms, because it was my problem, I’d guess the switch is the culprit, or more specifically, the power from the switch.