I have an intermittent problem that has croppped up where incoming calls drop to voice mail as soon as they are answered. When this happens, the person answering the call hears nothing on the receiver and the caller goes right to voicemail and does not hear the person answering the phone. When the person answering the incoming call hangs up and tries to call the caller back, the HT502 plays the "Device not registered" and will not allow any outgoing calls for about a minute. It then seems to reset itself and outgoing calls happen normally. Incoming calls are hit and miss; outgoing calls are fine as long as the above scenario didn't just occur.
There does not seem to be any rhyme or reason to why this is happening. Our 3.0Mbps DSL service tests out fine and it happens even when nothing else in the house is using the DSL connection. We have two HT502 boxes attached to our router (two separate Phonepower numbers on one account.) The older HT502 is the one that exhibits the problem. It is connected to our router directly via Ethernet cable and has the specific port assignments set up in the router's table. The second (newer) HT502 is set up in the router using the DMZ zone and has not exhibited the same issue. Could the original HT502 simply be going bad?
zyXel DSL modem (bridge mode)
Linksys WRT150N wireless router
HT502 (set up in router's port table - intermittent incoming calls drop to VM issue)
HT502 (second PP phone #; using router's DMZ)
Thanks in advance for any suggestions.