An OsmocomBB-compatible phone as transceiver for OpenBTS

I was going through different pages of osmocom-bb when i came through that statement: "The following how-to will guide you through the steps needed for using an OsmocomBB-compatible phone as transceiver for OpenBTS." on the following page: http://bb.osmocom.org/trac/wiki/Software/Transceiver As i have running OpenBTS on USRP1 board with 2 RFX900 daughter boards as Tx & Rx. I really didn't understand the meaning of the statement i mentioned above. What does it mean? Can anyone help me out?