I've seen this issue several times ever since the inception of the BCM450. What happens is usually on one particular port the phone attached will ring in a non standard way. It will be a long ring, not the standard on then off ring, and you cannot pick it up to make it stop ringing. Back in 2011 when I first saw this issue a lot on a new customer install rollout I found information on this website related to it that said the fix was to reseat the serial cables on the MBM backplane and the motherboard. This seemed to fix maybe 50% of the issues but not all of them. A lot of times we would just move the phone in question to another port to get rid of the issue. I'm wondering if anybody has had this issue and maybe has a more permanent fix? Thanks in advance for any possible solutions.