Keyboards
Today keyboards are readily available, inexpensive and have a standard interface. In 1973, new keyboards were only available to computer and terminal manufacturers. Surplus keyboards were available to hobbyists but they often produced codes other than ASCII, such as baudot or EBCDIC. The TV Typewriter project and kit did not include a keyboard. The unit on the September cover shows a keyboard project Don Lancaster did in the February 1973 issue. This project involved hand crafting 55 key-switches including fabricating the springs for each key-switch. Most hobbyists chose to use a surplus keyboard and modified it to produce ASCII codes. Don Lancaster's prototype TV Typewriter which is now on display at the Computer History Museum has a surplus keyboard with an ASCII encoder circuit that was published in the February 1974 issue of Radio-Electronics. The plans for this encoder were also included in the TV Typewriter booklet
Popular Electronics (April 1974) featured a complete keyboard kit designed by Don Lancaster and available from Southwest Technical Products for $39.50. The first version used simple RTL ICs to decode the key matrix. The design was soon improved to use a full featured keyboard encoder IC.
Read more about this topic: TV Typewriter