As a follow-on to my previous post about getting mobile internet, here’s one about getting voice service on your US phone (at least if you have a Sprint phone).

I have a Samsung Galaxy S4 on Sprint. Sprint’s CDMA voice network is incompatible with the GSM networks in most of the rest of the world, but recent Samsung Galaxy devices (at least the S3 and S4, and other devices of the same generation/platform) use a software-defined radio that can be made to speak GSM or CDMA at will, with a simple settings change. CDMA doesn’t require a SIM but LTE and GSM do, so the Galaxy is a de facto international phone.

Sprint lets you do international roaming calls for $2/min, which is absurdly high. It’s much better to get a SIM from a local carrier and use that. Making it do this is relatively simple. If your account is in good standing, a simple phone call to Sprint will unlock your phone for using other SIMs (and before you try to do this for a GSM carrier in the US, it explicitly does NOT work on AT&T or T-Mobile). This unlock process does require a data connection (mobile or Wi-Fi) for the phone to receive the unlock signal. After doing that, there’s a simple process that the Sprint rep will give you over the phone to complete the process.

Once that’s done (took me about 5 minutes on the phone – which I did via Skype from Haiti!), all you have to do is go find a local SIM (and in the case of the Galaxy, trim it down to size), pop it in the phone, switch it over to GSM in the Mobile Networks settings, pick your carrier, and off you go.

I’ll add screenshots just as soon as I can make the phone do them. The normal S4 tricks aren’t working.