Abstract: An improved calibration detection system for use in calibrating an electronic apparatus includes a processor apparatus, an evaluation apparatus, and a connection apparatus. The connection apparatus includes a plurality of leads and is operated by the processor apparatus to internally switch and connect the various leads with various elements of the evaluation apparatus. By enabling all of the leads to be connected at the outset with the electronic apparatus and by internally switching the connections between the leads and the various elements of the evaluation apparatus, the calibration detection system saves time and avoids error in performing a testing protocol.

Abstract: An improved calibration detection system for use in calibrating an electronic apparatus includes a processor apparatus, an evaluation apparatus, and a connection apparatus. The connection apparatus includes a plurality of leads and is operated by the processor apparatus to internally switch and connect the various leads with various elements of the evaluation apparatus. By enabling all of the leads to be connected at the outset with the electronic apparatus and by internally switching the connections between the leads and the various elements of the evaluation apparatus, the calibration detection system saves time and avoids error in performing a testing protocol.

Abstract: An air powered vacuum apparatus for use in an air vacuum excavation system creates a fluid flow under vacuum and reduces the sound level of the exhausting air. The apparatus comprises an injector assembly and a container for collecting spoil, i.e., dirt, sand, gravel, etc. drawn in from the excavation site. The vacuum is produced by an injector and a supersonic nozzle assembly in fluid communication with the container. The injector has converging, straight and diverging sections, and the supersonic nozzle assembly extends into the converging section. The supersonic air ejected from the nozzle assembly mixes with the air drawn up from the container, and the air mixture travels through the diverging section and out of the injector assembly and creates a vacuum in the container.