The IUSC (Integrated Universal Serial Controller) is a single-channel multple protocol data communications device with on-chip dual-channel DMA. The integration of a highspeed serial communications channel with a high performance DMA facilitates higher data throughput than is possible with discrete serial/DMA chip combinations. The buffer chaining capabilities combined with features like character counters, frame status block and buffer termination at the end of the frame facilitate sophisticated buffer management that can significantly reduce CPU overhead. The IUSC is software configurable to satisfy a wide variety of serial communications applications. Offered at 20 Mbit/sec, its fast data transfer rate and multiple protocol support make it ideal for applications in todays dynamic environment of changing specifications and ever increasing speed. The many programmable features allow the user to tune the device response to meet system requirements and adapt to future changes with software instead of redesigning hardware.