The Realtron, produced by Realtors Computer Service in 1967, was a system for storing, updating, and retrieving real estate listings over the phone. These brochures were printed in 1969. The RCS/Realtron logo is set in Gemini Computer, which must have been the typographic equivalent of high tech in the late 1960s.
Learn more from Travis Rosenbaum who acquired a Realtron device and fully restored it in 2021.