"This report describes a 4-in-diam borehole probe that contains a low light level television camera, magnetic compass, light illumination source, bottom-water detector sensor, and a point angle sensor. The camera viewing angle is at a right angle to the probe's body. All data from the sensor are multiplexed into the closed-circuit camera video for transmission on a single 50-ohm coaxial cable to a surface control unit. Likewise, control of the probe's power, zoom lens, focus, panning, and aperture is accomplished via a downlink multiplexed on the same cable." - NIOSHTIC-2 NIOSH no. 10004671

National Institute for Occupational Safety and Health