Serial I/O is the simplest form of communication supported by Windows CE. It is used when there is a direct, one-to-one connection between two devices. It can take place over a variety of hardware connections, but most Windows CE-based devices use simple serial cables or infrared transceivers. Transferring information over a serial cable connection is similar to reading from or writing to a file, and it uses some of the same functions. Windows CE also includes a set of functions used to manage the connection itself.
Windows CE allows direct serial I/O over an infrared link using the same serial communication functions that are used for wired connections. When using an infrared link, the I/O is "raw," which means that the bit stream is not processed in any way. For example, there is no collision detection in Windows CE.
The IrDA protocols provide more robust communication than raw infrared (IR). The IrDA protocols are available through Infrared Sockets (IrSock), which is an extension of Winsock. As an alternative to using IrSock directly, IrComm uses the same function calls as standard serial communication, but uses IrSock and the IrDA protocols internally.