Regulatory and legal files in connection with Maryland firm Preston Tracking Company's application for a cooperative use of microwave facilities of a motor carrier radio service system built and owned by Transportation Microwave Corporation [TMC] and leased by Preston and other carriers. FCC granted the application on February 18, 1971, but in August 1971, responding to petition for reconsideration filed on March 24, 1971 by Interdata Communications Inc., which stated that Preston proposed to provide a common carrier service and not a shared use of private microwave system, issued an inquiry on sharing private microwave facilities [FCC Docket No.19309]. At the same time, MCI-New York West [MCI Carrier] and Microwave Communications Inc. appealed FCC decision granting Preston application in the appellate court for the District of Columbia circuit [case 71-1753]. Files contain supporting material for Preston application; parties pleadings in rule making and legal proceedings, FCC orders and public notices, MCI preparatory material for the appeal proceeding [Preston work file].