I have been trying it with the POTS on line 1 and VoIP on line 2. As soon as I plug in VoIP I get a hum on Line 1. No hum on the VoIP line. The VoIP line is a straight single run from the cable modem/ATA to the phone. I have tried multiple cables. The cable does not pass any power lines.
If I switch the lines with VoIP on Line 1 and POTS on line 2 than the hum gets MUCH worse and it becomes much louder and sounds like more than a hum.
I think that I will try a different 2-line phone before trying the RF jack extender. Anyone have experience with the RCA 2-line phone (25202RE3). I can get a new one thru ebay for $70 which includes shipping.
