I think you are trying to connect both lines of an OBi202 6P4C (6 position 4 contact) RJ connector to a wall socket that has a 6P4C connector. Then your 2-line analog phone plugs into a different 6P4C connector elsewhere in your house. 6P4C connectors are 9.65 mm wide.
Have I misunderstood? You day your phone currently hooks to your router, and that is not what I would expect, unless your router also included an ATA.
After you have isolated your phone wires from the telephone company wires that leave your house, you will just use a 4-wire telephone cable that has 6P4C connectors. You will plug this into the Phone 1 jack on the OBi, and you will leave the Phone 2 connector with nothing plugged in.
Phone 1 has line 1 on the inner pair, and also has line 2 on the outer pair of the 4 contacts that it uses.
The Ethernet jack of the OBi will connect to the Netgear router for an ethernet connection.