A unique multi-user computer system for data acquisition and experimental. control is now in use at the US Army Research Institute of Environmental Medicine at Natick, MA. Based on a 32K PDP-11/40 which is running the multi-task executive RSX-11M, the system provides real-time data acquisition and control for several independent biomedical experiments simultaneously. The system handles analog I/O (64 channels in, 10 out) through the LPS 11, switch closure input, relay closure output, parallel binary or BCD I/O (DR 11 interface) and TTY I/O (DL 11 interface). Analog and digital signals are carried to and from approximately 20 laboratories in the building via cables of 11-pair individually shielded wire. Instrumentation amplifier modules (Analog Devices AD610J) preceded by passive filter networks are used at the computer end to isolate and filter each analog input channel at a cost of approximately $50/channel. Applications which have been developed include: analysis of myocardial constractility, breath-by-breath respiratory parameter evaluation, temperature (skin and rectal) measurement and digitizing of miscellaneous graphical data. No automatic control is presently being done, but on-line manual control is being done based on data fed back to the labs in the real time from the computer.