For about a month, ISY994 v5.3.4 has stopped talking to my X10 devices. Today, it has stopped talking to any of our Insteon devices. All of the Z-Wave devices still work. As far as I can tell, ISY is still talking to the PLM, when I ask for its status, it returns a result. All of the Insteon and X-10 devices are still properly controlled by HomeLinc and any keypads around the house. The UD admin console has ! marks for all insteon devices.