I am having issues with sets/DN's with Answer DN buttons programmed locking up (I/C and answer buttons lit up and unresponsive) regularly (once a week or so). I have to disable and re-enable the port to correct. Just unplugging and plugging back in doesnt really help. The system has no patches applied and I can not find a patch for this issue. Any help on a patch or resolution would be appreciated. Let me know if more info is needed.