CompactDAQ from National Instruments, Austin, TX, is a USB-based modular DA system for sensor and electrical measurements on the bench top, in the field, or on the production line. The system offers an 8-slot chassis that accepts I/O modules capable of measuring up to 256 channels of electrical, physical, mechanical, and acoustic signals. All modules are hot-swappable and autodetectable and offer up to 2300 Vrms of isolation. Four dedicated USB signal streams provide synchronous analog and digital I/O. Possible measurements include voltage, temperature, strain, sound and vibration, digital I/O, and switching.