It's not that simple. When you were a kid, your house may have been wired with 4 wire phone cable, with each wire connected, even though only red and green were live. Adding a second line usually meant they connected the other two wires for that line. Then, at any jack, you could split the wires to two jacks or get the adapter that you're talking about.
Your current home MAY be wired the same. It may also be wired with 4 wire cable, but only 2 wires are connected. This is VERY common. You should check both where the wire feeds the house AND at each phone jack. Then, instead of buying adapters, you can choose how you want to feed that signal throughout the house, i.e. most jacks use red/green for the primary service, and a limited number of jacks use the other two wires for the secondary service. Then, you just have to ensure that the correct OBi phone ports are feeding the correct jacks. I don't have a 202, but MY understanding is that each port can handle any of the 4 services, you configure that in the OBi, and then feed a phone cord from that port to your wall jack. If using a standalone phone, you can plug it right into the OBi.