Two decades have passed since the convergence of digital technology and the pH meter. This year has brought another convergence, this time involving four technologies: the pH meter, the handheld computer, the silicon chip-based pH sensor, and the Internet. The first of this new generation of pH systems is the IQ400 which consists of a pH module attached to an expansion slot in the top of the handheld computer. The result is a powerful and versatile pH meter.