You don't really see cool little designs like that anymore - it's all almost all digital now. Though I will say YIGs and RF designs are pretty cool in terms of combining mechanical with electrical elements. Maybe it's just nostalgia, but I miss when electronics weren't so standardized. Tube amps, flip displays, tube displays, etc.
On the other hand, this forced people to make written appointments for calls. Sometimes I wish that happened more often.
We know we can call each other on phone any time of any day and the other would nt mind one bit about their routine or focus being disturbed.
Still we plan our calls a week in advance and only have calls once every few months.
Part of the reason must be that async but near-instant communication afforded by messaging apps is enough for 90% of the needs.
Of course this reduces the intimacy of having a real conversation but we are introverts anyway.
You don't?
[1] https://1889victorianrestoration.blogspot.com/2011/09/everyt...
PS Little further back maybe but there is a nice outline of how the naval Semaphore system got started in the James Burke Connections (S3E08) [1] -- I was looking for one where he got into circa Roman long distance fire signaling and how they got significant bits to work
I would love to hear it!