At least for clocks, I have seen (used, owned) a number of WWV controlled models with: - a slide switch for the zone (EST/CST/MST/PST) - a DST on/off switch
Example: https://www.pinterest.com/pin/cool-clock-with-dst-switch--108227197265304889/ -- Steven R. Loomis Code Hive Tx, LLC https://codehivetx.us > On Dec 13, 2024, at 12:48 AM, Guy Harris via tz <tz@iana.org> wrote: > > On Dec 12, 2024, at 8:46 AM, Brian Park via tz <tz@iana.org> wrote: > >> One thing rarely mentioned in these discussions is the millions of >> electronic devices (e.g. timers, clocks, watches, thermostats, etc) which >> are hardcoded to handle DST using the current US/Canada rules (i.e. first >> Sunday in Nov, second Sunday in Mar). If the DST rules are changed, those >> devices will become obsolete because the firmware for those things will >> never be updated. > > So do they sell special models in Arizona (along with the regular model, for > residents of the Navajo Nation)? > > Or do they have, for example, a switch that controls whether to observe DST > or not?
