The portable mainframe is the base component of a customer-configurable portable instrument. It can function as a logic analyzer, a digital storage oscilloscope, or both, depending on the module cards installed in its slots. The portable mainframe has the following features: Microsoft Windows operating system Standard PC I/O ports, two PCMCIA PC card slots, two USB ports, and a PC-based 266 MHz Intel Pentium with MMX processor architecture that provides automatic connectivity to numerous off-the-shelf I/O devices (Ethernet, modem, printers, etc.) Display system provides internal color flat-panel LCD display and an external SVGA port capable of driving large, high-resolution external monitors Four backplane slots provide compatibility with TLA 700 Series instrument modules Precision clock, bus trigger line, and event signaling between the mainframe and instrument modules supports real-time triggering, sequencing, and time correlation of events Mainframe compatible with international power standards, certified to international safety and EMC requirements, and tested to rugged environ- mental standards