Book excerpt: When PCs and peripherals began showing up with USB ports in the late 1990s, many predicted that legacy serial (COM) ports would soon be obsolete. The predictions were wrong. While most standard peripherals now use USB, serial ports are the interface of choice for devices that require simple programming, long cables, operation in harsh environments, or basic networking capabilities. Serial ports are more versatile then ever due to developments such as USB virtual COM ports, the .NET SerialPort class, enhanced microcontroller USARTs, and new wireless interfaces. Serial Port Complete Second Edition is a completely revised and updated guide to programming and interfacing to COM ports, USB virtual COM ports, and serial ports in embedded systems. Author Jan Axelson shows how to: § Access COM ports using the SerialPort class in Microsoft’s .NET Framework. § Program embedded systems for serial-port communications. § Design and program USB devices accessed as virtual COM ports. § Upgrade RS-232 designs to USB with no changes to host software or device firmware. § Design circuits for electrically harsh environments. § Create serial networks of embedded systems and PCs. § Use serial ports in wireless links. Example code is provided for PCs and embedded systems in both Basic and C/C#. The author maintains a website with articles, program code, and other links of interest to developers of serial-port applications (janaxelson.com).