Best practice international GSM setup

[fsotirop]

Originally Posted by hwa

I have and plan to use an iPhone4. Although it doesn't seem to support seamless callback all providers give you the USSD to use to make a call. It's a pain but something I can live with. Maybe there's an APP that will take a number from my phonebook and prepend and append the necessary strings to the number to be dialed. I know there are options to make an iPhone take a dual sim but that's too much for my use case.

the best callback voip provider at the moment is: http://www.callimax.com/
great rates with per second billing

manual callback works great. tested for several months.
android app not working, haven't used iphone app to comment