RasPiComm FAQ answers all your questions and could be easily found by googling for "RasPiComm". Even more info could be found in RasPiComm technical specs.
Well, for people who cannot read FAQ, here's a short quote:
Q: What is the RasPiComm?
A: It is a piggyback extension board for the RaspberryPi.
Basically, it's a board you connect to the RaspberryPi to get some extra functionality, like communucation ports, LEDs, HW clock and more (read RasPiComm technical specs for details).
What do you need to use it? -- well, you need RaspberryPi with power supply and SD card to boot from and, basically, RasPiComm itself. Or maybe you don't need RasPiComm -- I don't know, that depends on what's your purpose -- probably you need a completely different setup altogether.
What do you need to make it work? -- connect all connectors, insert SD card, attach power and see what happens. If there's no smoke -- it works, if there's a smoke -- disconnect the power and try to find the cause. Please, don't inhale, may be hazardous for your health.
Any software you need for it? -- obviously, the browser, preferably Mozilla or Chrome, to read the plethora of online pages with the information pertaining to RaspberryPi and RasPiComm.