Air-Byte IR Transceiver is a PIC based tranceiver that transmit & receive infrared signals with your PC serial port. The project provides a simple method for receiving serial data on one pin, and outputting serial data on another modulated at the IR detectors band-pass frequency.
The brain of the Air-Byte transceiver is a tiny 8-pin PIC12F508 microcontroller. Operation is simple. The PIC simply monitors GPIO,0 connected to the PC serial port TX pin #3. When this pin transitions from logic low to logic high, the 12F508 generates the 40kHz IR carrier. During low periods the carrier is suppressed.
Documentation of IR tranceiver