Telenet was the first commercial packet-switched telecommunications network. It was purchased by GTE in 1979, and at about that time I was involved with maintenance of the Telenet Access Controller (TAC) terminal concentrator in Austin, Texas. The main switching node was in Dallas, and the Austin TAC was located inside the building of the small company where I worked. I was the sole electrical engineer at this small company, and I would swap out boards and modems in the TAC racks as needed. I also travelled to San Antonio to work on a small TAC site there. I continued doing this sporatically (there wasn't much maintenance required) through early 1982, when the small company in Austin went out of business and eventually sold the building.
Bill