Verizon "Home Phone"

RLS7201 wrote:
You might try a Ferrite noise filter on the ground lines.
Cheap and easy to try. The more passes you make throught the filter, the better it works.
We had a simular issue with a 12 volt Blue Ray player and our 12 volt TV. The Ferrite filter on the ground wires fixed our problem.
We also use a Verizon Home Phone Connect. Both at home and in the RV, using the RV batteries and a cradel phone when on the road. Best deal in town.
Ferrite Filters

Richard

We've (me & OP) have been talking via PM. He's done all the homework and is correct that it's a common ground rail problem, and the manfacturer expects an AC wall work that by default floats ground from the rest of the world. His solution of a DC-DC converter is the right, and maybe only one to get around a really cheaped out design.