A term dreamt up by the VoIP community to distinguish software
applications capable of making VoIP calls to physical hardware devices
(phones, adapters - hardphones) which can also make
VoIP telephone calls.
These are all PC to PC VoIP telephony so you need your computer to make
VoIP calls with SoftPhones, you still need a headset or speakers and
microphone of course to actually do the speaking and listening bit.