I purchased 2 SPA3102 units, first to address a separate problem, but then in the hopes of virtualizing the FreePBX server.
The first unit worked great.
I went to install the second unit, it will not recognize the phone line. The green light for phone never comes on, and the PTSN shows inactive as if it doesn’t see the line. I compared it to the working one to be sure.
The key difference is the this unit is connected to a multisite Centrex system whereas the other line is direct from the phone company.