Jirateep:
Please look at this link. It will introduce you to IR communications concepts.

Then look at this link for some information on the way IR transmissions to a Sony product are formatted.

To transmit to the Sony you will need an NPN transistor connected to a port pin that can drive a IR LED. I would suggesting using the T2 pin from an 8052 derivative with a TIMER2. Program the TIMER2 to output a 38KHz square wave to the T2 output pin. (You could also use a channel of a PCA it that is available instead). Next you setup a 2nd timer that runs a sequential state machine that steps through the basic bit cell (pulse structure) of the Sony protocol. This second timer ISR will enable and disable the output from the first timer that produces the 38KHz drive to the IR LED. The state machine uses the data contained in two memory locations to determine the IR code to transmit. Your main line code will contain code to setup the code to send into these variables and the start timer interrupt state machine, and finally poll till the transmission is complete.

I hope this helps.
Michael Karas