I bought a pair of Powerline Adapters about a year ago to network the HR21 box in my office. I was never able to get more than random weak connectivity with them despite heroic efforts on my part, including replacing wall outlets, cleaning all contact surfaces, isolating outlets and only using the Adapters on them, etc, etc. I also checked my house ground setup and its good. I gave up and bought a WGA600N from D* and usd it. Its a good solution, DOD is fast and reliable. I have a heat pump and for several years the fan would intermittently turn on 5 minutes before the compressor. The compressor has, of all things, a 5 minute low voltage delay circuit. Hmmmmmm. The system always checked OK when the HVAC tech looked at it so we figured we were getting intermittent low power from Pennsylvania Power & Light. The plot thickens. Several years ago PP&L replaced my meter with a remote reading meter. This may have something to do with the fan-before-compressor problem. But wait - there's more ($1 to Billy Mays). My heating system doesn't have resistance auxiliary heat like most heat pumps. In the 80s PP&L came up with a Residential Thermal Storage (RTS) program to promote heat pumps. My house has a 300 gal hot water tank which was heated during off peak hours. I got ridiculously low rates for using this system. In fact they were so low that the Oil Dealers successfully sued PP&L in the 90s and forced them to cancel new installations. The tank heater control is actuated by a signal from the electric meter. So, my meter controls the Thermal Storage relay and is remotely read. Fast forward to 2010. As of Jan 1 PP&Ls rates are deregulated. PP&L cancels the RTS program - goodbye cheap power. My rate is scheduled to increase by 40% or so. I call PP&L and they come out and disable the thermal storage relay in the meter (the relay also blocked the domestic hot water circuit). A few weeks later I notice that my heat pump compressor isn't randomly being held off any more. Hmmmm!! The last part - I have an H21 box which I wanted to network for MRV. I was going to get another WGA600n but just for drill I connected it up with the Powerline Adapters. Bingo - a perfect connection with no manual settings required. I even have the adapter near the box plugged into a surge protector. Logic would say that a relay controller couldn't have been the cause of my problems but who knows. It may have been faulty and chattering, injecting noise or ???? Anyhow I'm now ready for MRV beta if D* would only update my HR21-100 and H21 boxes. It'll be a good test - an HR21 directly connected to a Linksys WRT320N router, an HR21-200 connected via a WGA600N, and an H21 connected via Powerline Adapters. I hope it works because I don't want to use DECA, although switching to SWM has freed up some space in my cableways so I can probably get cat5 to my boxes if necessary. Thats my story and I'm sticking to it.