This is a protocol defining 22kHz pulses which are sent by a DiSeqC-enabled satellite receiver up the co-ax to the LNB (or to an LNB switch, or a DiSeqC motor, or some other peripheral).
v1.0 is only able to operate a switch (eg to select between LNBs on fixed dish(es).
v1.2 is able to operate a special motor that after suitable calibration effectively turns your DiSeqC-enabled receiver into a receiver+positioner.
You may like to refer to a general satellite lexicon or glossary. There are many online (use AltaVista to search) and many satellite magazines carry such (eg the UK publication What Satellite).