[John Graham-Cumming] has shown us one exquisite example, with his teardown of a simple Czech telephone. The model in question is a DS3600 telephone built by Tesla Stropkov in the early 1980s.

Why Making Old-Fashioned Phone Calls Is More Important Than Ever In a world dominated by text messages, social media, and instant communication, the art of making a good old-fashioned phone call ...

The schematic for the project shows how to connect the rotary dial (salvaged from an old telephone) to both a 7-segment display and a collection of ten LEDs.