Ah, those switches ...
There's a ton of 'em. Some are branded KPT, which are from a company called Keypot. Some are branded TEC. There are also various unbranded varieties. It's extremely hard to unravel, as most of these companies (except KPT, who were fairly prominent) seem to have been short-lived, and I can't work out what went on there.
I have no expectation of ever figuring these out.
The Alps vortex cannot truly be conquered; I simply tracked down most if not all of the major brands by way of the existing companies who sell or previously sold the switches. These companies are all gone and have taken their secrets to the grave with them.
