The Agilent/HP 1640A Serial Data Analyzer offers an efficient method for locating faulty system components in conputer networks or, in general, anywhere RS-232C (V24) serial interfaces are used. The network may be small, consisting of a minicomputer or microprocessor and a few terminals, or a complex, centralized CPU-based communications network, either of which require rapid problem locationation to minimize system downtime. The 1640A can also be used during system design for debugging software, during systems integration, and for preventive maintenance.