Meeting communication signal requirements is the first thing that you need to solve, as the circuit you initially posted absolutely will not work because RS232 signal levels between 3 volts and -3 volts are invalid. You must provide a negative supply so that you can drive TxD to levels below -3 volts and above +3 volts. The MAX232 and similar parts provide those acceptable levels.

If you intend to use the RS232-compatible serial port on your PC, you should probably have a look at the standard, at least to the depth to which it is described on the www. Providing "legal" levels on that interface is a "necessary-but-not-necessarily-sufficient" condition. Failure to do will ensure that your effort will NOT succeed, but providing those levels will not necessarily guarantee that your effort succeeds.

RE