You can pose those questions on the maplin web site. One of the ones I have free runs and samples every second and outputs a fixed baudrate ASCII string after each data capture. Others output in response to a single character input. If you set terminal echo on, /some/ models of the latter will take one of the echo characters as the trigger and just keep doing conversion after conversion. It doesn't seem to matter that it is getting many trigger characters that it doesn't use. I can't promise that this little klduge will always work though.
Thus the protocol is very, very simple and it would be a doddle to write your own software - assuming that you /can/ write software, that is! There are public domain libriaries/dll for Windows that make it easy to set up and utilise a serial port - although development envirnments like Delphi often already have them.