Playing with my Obi2182, and saw in the configuration screen this. There's even a LINE status screen. But the only CAT3 jack in my Obi2182 is the "Aux" jack.
Can I indeed plug my Obi2182 into my wall and have a landline connection to my Obi2182?
The 2182 can be connected to a POTS line but requires an OBiLINE adaptor. This plugs in to a USB socket on the 2182 and has an analogue phone jack for a cable to the wall jack.
Attempting to connect the wall jack directly to any socket on the 2182 will not work and has a high probability of permanently damaging the 2182.
The OBiLINE was discontinued several years ago.
https://www.amazon.com/OBiLINE-Adapter-Devices-OBi1062-OBi1032/dp/B00DP4YOJ6