A long-distance multipoint telemetering system using teletype transmission

This paper describes a point-to-point telemetering system using pulse width modulation and sequential scanning for transmission of several measured variables over a single circuit by teletype. The system, which is essentially electromechanical rather than electronic, operates on the basic principle whereby the magnitude of a measured variable is converted into a pulse of proportional time width. The system was developed specifically for remote monitoring of pumping stations on a pipeline to permit automatic operation from a central dispatch office. In the design of the equipment emphasis was placed on requirements of reliability, sturdiness, simplicity, and ease of servicing rather than on factors such as high speed and excessive sensitivity.