Abstract: The digital pressure gauge system is particularly useful for reading blood pressures of humans, and has general utility in dial or disc type gauges for reading liquid and gas pressures. The digital pressure gauge system includes a rotary encoder which takes the place of the dial or disc of a conventional pressure gauge and therefore rotates to a degree proportional to the magnitude of the pressure being read. The rotary encoder carries a plurality of light sources which are selectively located for encoding particular angular positions of the rotary encoder. These light sources selectively direct light on photosensors which are connected by circuitry to digital readouts for converting the encoded information into a digital display. The displays may be contained in the gauge unit or they may be located remotely from the gauge unit if desired.