[GreenKeys] WW2 IBM radioteletype network?

[hwhall@aol.com]

> IBM predates WWI.
> 
> The clocks were an early product, which was eventually spun off as 
> "Simplex". The Simplex clock business is
> still around, after far too many mergers and sales, as
> 
> https://simplextimerecorder.com
> 
> Those classic clocks were controlled by tones over the power line. There 
> are some filters and thyatrons inside each clock.

The clocks I'm working on predate the simplex concept. These don't connect via the power lines. They run off pulsed 24v DC provided via three wires from a master clock. So, they required dedicated wiring in a building/installation. I have to build little driver boards for them, once we have them working again.

Here's an identical one that's been offered for sale for a long time:
https://www.surplussales.com/items/99231/ibm-24-hour-military-clock/

Wayne
WB4OGM