I have downloded the control software library for an RFID reader from the philips website and it consists of 8 source files(.C) related to the reader, 3 source files related to the RFID tag, three header files(.H) defining functions and data structures, there is reg51.H and portab.H in there for 8051 specific language definitions and finaly a library binary file control.lib. It could be that control.lib is the library made up by compiling all of the above source and header files. Seperate from all that i have a test source file file that contains main() in order to test the library , so how can that be done in the keil c51 compiler. In other words how can one add a library from outside and use with a source file.