The OPLink is a radio transceiver backed by a ARM32 powered digital packet processor specifically designed for the OpenPilot project, it was originally developed under the codename:
PipXtreme and there are many artifacts still that reflect this. Its a two way radio system allowing real time telimetry information for the Ground Control Station, Wireless Configuration and even Radio Control from your transmitter over a single communications link. You will need two modems to establish a connection.