My approach would be to disconnect everything from the house, all phones and Ooma.
Measure between the two house wires with the voltmeter to see if there is any voltage either AC or DC.
Measure from each wire to earth ground for voltage.
There should not be any voltage detected for any of these measurements.
If that test passes, then use the ohmmeter to measure the resistance between the two wires.
That reading should be infinite resistance.
Measure the resistance from each wire to earth ground. Again the resistance should be infinite.
The typical problem is that the wires were stapled to the house with the wrong kind of staples and over time the staple wears through the insulation and creates a short between the wires. It can take years for the short to develop at a low enough resistance to cause a problem.
Telo with 2 Handsets, a Linx, and a Safety Phone
Telo2 with 2 Handsets and a Linx
Could there have been a FW update that is having unintended consequences?
Check each jack to see if the pins are straight and in place.
Two if by Sea
Three if by Limo
Update *** I have my ooma feeding a 1x8 phone port from On-q (http://www.legrand.us/onq/voice-data-co ... EOiSKSe7Zc which then goes directly to each jack.. I unplugged all the cat 5 cables from that 8-port and plugged in only one jack at a time and the phone worked. I then plugged in the other jacks and the phone still works.
I noticed this happened after the power blinked on and off during a storm. Som how it got confused or something.