The History of the TV Typewriter


Computer Terminal Corporation, Datapoint 3300, 1967The standard user interface to a computer in the early 1960s was punch cards and a line printer. CRT displays were rare and each computer manufacture had a unique character code and electrical interface. By the mid 1960s time share systems using ASR-33 Teletypes became popular for remote users. In 1967 Computer Terminal Corporation came out with a video terminal that emulated the ASR-33 so the time sharing companies would not have to modify their software. It was called the Datapoint 3300. This terminal was very popular and was sold by several computer companies including DEC (VT06) and HP (2600A).



Don Lancaster was a frequent author of articles in hobbyist electronics magazines. The January 1967 issue Popular Electronics featured his IC-67 metal locator project and this started a successful relationship with Daniel Meyer of Southwest Technical Products Corp. SWTPC sold kits of construction projects that were published in Popular Electronics and later Radio-Electronics. The solid state projects needed printed circuit boards and some of the parts were difficult for individuals to obtain. This time period was a heyday for the kit business with Dan designing the audio projects and Don designing the digital projects. (Don was never an employee.)



Don Lancaster's day job was at Goodyear Aerospace in Phoenix, Arizona. Around 1973 Goodyear was designing a high resolution video display that gave Don the inspiration to design a low cost TV Typewriter. This appeared in the September 1973 issues of Radio-Electronics. With professional terminals costing a $1000 this $120 kit looked like a bargain. To keep the cost down the design used shift-register memory, this was the common method at that time. The cover story and the design had a big impact on the hobbyist community at the time.



There were some problems that limited its success. First some of the parts were difficult to get, there were letters to the editor complaining about that. The TV Typewriter was not sold as a complete kit. It did not include a keyboard or a serial interface. The design was very compact making assembly challenging. Don provided a keyboard in the April 1974 issue of Popular Electronics. That keyboard was wildly popular and sold by SWTPC for years. The Apple 1 computer on display at the Computer History Museum has this keyboard.



Daniel Meyer met a design engineer named Ed Colle at a sign company bankruptcy auction in San Antonio. Ed was the engineer on a 2000 character 300 kilowatt message board. Previously Ed had worked with Datapoint on terminal design so he made an 80 character by 25 line terminal for the sign board. Dan saw the terminal and asked Ed to design a terminal for SWTPC.

The SWTPC CT-1024 Terminal was reduced to 32 characters by 16 lines without scrolling. It used common TTL parts and 2102 static RAMS. The boards were laid out with very loose part spacing and wide traces to make it easy to assemble. A complete set of option boards were offered including a serial interface.

1976 SWTPC CatalogThe design was finished by July of 1974 and submitted to Radio-Electronics. It was finally offered for sale in January of 1975