The SigmaTel STIr4200 was an infrared (IrDA) transceiver chip designed to facilitate wireless data communication between devices using infrared technology. Commonly integrated into laptops, PDAs, and other portable devices, the STIr4200 enables efficient and reliable short-range communication without the need for physical cables.

Key features of the SigmaTel STIr4200 include its support for various IrDA data rates, ranging from SIR (Serial Infrared, up to 115.2 kbps) to FIR (Fast Infrared, up to 4 Mbps). This broad compatibility ensures that it can communicate with a wide range of infrared-enabled devices, providing flexibility and convenience for users. The chip's compact design and low power consumption make it an ideal choice for portable and battery-operated devices, ensuring that it can be integrated without significantly impacting battery life.