The main reason I mentioned it is that I know I've seen various implementations--they're just not widely adopted. I guess nobody has the business interest to make it all work?
https://en.wikipedia.org/wiki/Radio_Data_System (FM radio) I figured this had an implementation considering text has been around for years. Amazingly, I don't think I've ever seen a car stereo use it to set the time!
https://en.wikipedia.org/wiki/Extended_Data_Services (NTSC) looks like a 2008 standard and most PBS stations provide "autoclock" time data
https://en.wikipedia.org/wiki/Radio_Data_System (FM radio) I figured this had an implementation considering text has been around for years. Amazingly, I don't think I've ever seen a car stereo use it to set the time!
https://en.wikipedia.org/wiki/Broadband_over_power_lines I know this has been around but has had a lot of hurdles. I figured the current time might be a simpler thing.
The only reliably time-setting tech I've seen integrated is GPS--I'm not 100% sure how time zones work with it, but it does know your location.