Hi Brett:
The OBiTALK device has no idea what brand, model, or type of telephone is connected. All it knows is whether or not the proper voltages are appearing on the phone jack. If your phone's base station (I assume you mean its built-in speakerphone) works, but your cordless handsets don't work, then you have a problem with your cordless phone system. Seek support for that product. You can take the phone system to some other location, with working phone service, and see how it behaves there. You can also plug in some other telephone into the OBi's phone jack, to confirm that there is nothing wrong with the OBi, although you probably proved that already if the speakerphone works.