I don't know what methodology Shirley's company used

I don't know what methodology Shirley's company used. But yes, Teletype machines were very common in the mid-1960s. For example, Tymshare, where I worked for several years, was founded in 1964. Their customers used Teletype machines at their own locations, dialing into a Tymshare mainframe and paying by the hour. There were a number of similar timesharing companies in that era. Call Computer and Dial Data come to mind, along with Transdata where I worked in Phoenix before moving to the Bay Area. https://en.wikipedia.org/wiki/Time-sharing https://en.wikipedia.org/wiki/Tymshare https://en.wikipedia.org/wiki/Teleprinter I had an office at Tymshare's Cupertino headquarters, and a Teletype at home to work remotely. This proved handy one year when the company was doing some final acceptance tests on the Xerox Data Systems (XDS) Sigma 7. The problem was that all of us preferred the competing DEC PDP-10. So the company really wanted those tests to fail. My manager called me into his office one day and said, "This conversation is strictly between you and me. …