Before modern CRTs with ancient VGA connectors, and before fancy video terminals, the display for computers large and slightly smaller was the Teletype. While many of these Teletypes were connected directly, they were designed to be a remote terminal, connected through Ma Bell’s network. [NeXT] over on the Vintage Computer Forums is bringing the iconic ASR33 Teletype into the 21st century by giving this old display a modern way to connect to the outside world.
If you ever see a Teletype in action, it will be connected to a local machine. This was certainly not always the case. The Teletype was designed to connect to remote systems. [NeXT]’s Teletype came with a Call Control Unit designed for Telex lines, which do not exist anymore. Modems for the ASR33 existed, but good luck finding one. Lucky for [NeXT], nearly every modem ever made is backwards-compatible with the Bell Dataphone, one of the standard ways of plugging a Teletype into a phone line. All [NeXT] had to do was put a modem inside this Teletype.
With relays, transistors, LEDs, and a lot of perfboard, [NeXT] successfully built a circuit that would interface the Teletype’s Call Control Unit to a Hayes Smartmodem tucked away inside the stand. Believe it or not, this is an exceptionally useful build; if you ever find a Teletype tucked away in the back of an old office, in a surplus shop, or on Craigslist, odds are it won’t be compatible with any modern electronics. That’s not to say land lines are particularly modern, but since there’s a microcontroller included in the new circuitry, it’s relatively easy to add a USB port to this ancient terminal.