The National Instruments CF-6004 Data Acquisition (DAQ) device offers a compact and efficient handheld measurement solution, with dimensions of less than 16 cm². Designed for integration into Type II CompactFlash slots, this device is compatible with a variety of PDAs, making it ideal for portable applications in fields such as biomedical computing, field monitoring, diagnostics, and data logging. The CF-6004 features four single-ended analog input channels with an aggregate sampling rate of up to 132 kS/s and a resolution of 14 bits, ensuring precise data acquisition with a specified integral nonlinearity (INL) of ±1 least significant bit (LSB). The device's digital I/O capabilities include four programmable push-pull lines that can be configured either as static digital inputs or outputs, operating at a voltage of 3.3 V LVCMOS and LVTTL. The device is designed for minimal interference with high-impedance input when powered on, facilitating reliable data transfer under various conditions. Included with the CF-6004 is the NI-DAQmx Base software, which features a portion of the NI-DAQmx programming interface and is particularly well-suited for creating customized handheld DAQ applications using the NI LabVIEW PDA module for PocketPC. With multiple connection options and a robust architecture, the CF-6004 is a versatile tool for demanding measurement tasks in constrained environments.