I am located in Hong Kong, where the home automation isn’t popular at all, so I might need to import devices from overseas like from the US, does Z-wave require to talk to all devices on same frequency? I am worrying that if I purchase the wrong unit and I wouldn’t be able to use at all.
Take a look at the following. You are right to be careful about the frequency of the device and yes your devices need to be on the same frequency.
so when I look at a product on Amazon, how do I know what frequency does it run?
By the way, does Z-wave dongle being able to communicate multiple frequency at the same time or it have to stick to one frequency after configuration is done?
Unless they state the frequency, I would assume it is for the US.
Depends which dongle, but the AEON z-stick that I use is only one frequency. I would assume the same for others.
Best of luck !