Over on his channel SignalsEverywhere, Corrosive has uploaded a video showing us how we can create a full duplex packet radio communications system using two PlutoSDRs. Full duplex is the ability to transmit and receive at the same time. A single PlutoSDR is only half-duplex/simplex because it can only either receive or transmit at any one time. The PlutoSDR is a low cost (typically $99 - $149) RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range. 

On his video Corrosive explains how full duplex operation is desirable for amateur packet radio communications as it allows for faster and more continuous exchanges.  Demonstrations are performed with his PlutoSDR, SoundModem, EasyTerm, and SDRAngel. Later in the video he also speculates how it might be possible to do things like IP networks via the amateur radio bands with full duplex SDRs.