This application note strives to impart core, fundamental programming concepts and design considerations for the development of Palm OS® application programs. Attention is given to each of the fundamental areas of Palm OS application development in the “C” programming language. A Palm OS application program to interface to an embedded system via IrCOMM is included in the Appendices of this application note. This source code shows the system calls that can be used for IR communication. This application note begins with a discussion of the basics of the Palm OS environment, including resource limitations, tasking model, user interface basics and deployment options. Palm OS application developers must understand these basic boundaries to successfully develop for this platform. As the application note progresses, more detailed information conveys the specifics of communications programming for the Palm OS platform.