This is a 4 digit TIL311 display board that was used for a lot of microprocessor debug. Back when dinosaurs roamed, there was no easy way to capture the state of a processor data or address bus. Only top labs could afford a logic analyzer. Each TIL311 could capture 4 bits off a processor bus at over 10MHz. By placing 4 displays on a board, it was possible to capture a full 16-bit address bus state. This was useful for fixing hardware and software issues in early micro systems. TIL311 was expensive as a part, but they were so useful.
For example, a TIL311 display could help find where your code locked up, When the display froze, the offending address could be read. This was much easier than reading a row of 16 LEDs. The address could be cross referenced back to the linker file or the assembler listing. The TIL311 was also useful for showing raw parallel data from an ADC.
The strobe input of TIL311 is able to capture a fast event at typical TTL logic speeds. Each display works just like a 4-bit transparent D-flop for capturing a state.
In summay, TIL311 isn't about some pretty retro display and 24 hour clocks. It's a tiny 10MHz logic state analyzer. Not bad for late '70s technology.