The Linx KH2 transmitter uses the Holtek HT640 encoder, and I have posted code to decode this particular IC here http://www.picbasic.co.uk/forum/showthread.php?t=6581

Of course, since this is a forum for MicroEngineering Labs compilers, the code is for the PBP compiler.

If you need this translated to an 8051 core device, in C, I can do that, but there will be a charge for the conversion work.