A simple screw fit makes both the pressure and electrical connections without the need for tools, sealing tape, cables or plugs and digital characterization allows interchangeability without set-up or calibration. The modules can be changed in a few seconds to re-range an instrument at a fraction of the cost of a new one. The pressure modules can be used in conjunction with the relevant pneumatic or hydraulic pressure stations and the DPI 620 multifunction calibrator to form an integrated pressure calibrator for test and calibration of pressure instruments including transmitters, transducers, switches, gauges, and indicators.