I'm a radio technician and couldn't connect this to my existing 00621w2. I followed all the reboot and hookup instructions, except physically discharged the capacitors on the 00621 board, which I didn't need to do to discharge the power. I tried all three channels and checked with a portable radio that the transducer is actually transmitting at 433MHz. Bottom line, the two devices aren't compatible, despite Acurite's claims. 00621w2 has no humidity function and no multiple receiving channels. Although the two sensors look the same, they're not, and no matter how much it cost me to return it, it wasn't worth the purchase. I've had the device for 6 years, I was hoping it would last longer than it did. I would have just repaired the existing one, but the board was too rusted to fix and that was because it wasn't exposed to direct rain and sunlight. I would hate to see what any of these items will look like in 6 years time. This will be my last Acurite product, Davis and La Crosse make great weather monitors that I will be switching to.