Over 10 years ago, I started to make a habit of running around with a Vonage analog telephone adapter box to keep using a US phone number while on assignment or otherwise in Asia, Europe and South America and also while at home in the US. I also paid for the softphone option with the Vonage US numbers to make/take those US phone numbers' calls on my laptops. I still have the personal Vonage ATAs in Europe and in Asia but I've shelved them several years ago.

I could still see a setup like this being useful for others, but I've given up on traveling with the ATA boxex. Wifi calling from smartphones/tablets/latpops has become sufficient for my routine needs nowadays.