Abstract: An auxiliary unit is used in conjunction with a personal computer based work station for interconnecting the work station to an audio-visual communications network. The auxiliary unit includes a CRT, a camera, a speaker phone circuit, and a CPU for interfacing these elements with each other and with the communications network to permit the transmission and reception of voice, video and computer graphics information.

Abstract: The depth and lateral offset position of an underground pipeline or the like is calculated by a surface located instrument carrying two spaced sets of orthogonal antennas sensing electromagnetic energy induced in and radiated from the pipeline. The resulting four signals are compared in amplitude to derive by simple triangulation calculations the depth and offset distances in a simple computer-display unit. Thus a set of continuous reading may be made automatically by a self-contained portable unit as an operator tracks the pipeline to make a survey. The readings may be recorded upon a medium advanced by a measuring instrument as a survey progresses along a pipeline.