These are Hoiio's calling methods. Some of the calling methods might not be available depending on your smartphone's OS and your country.

Call Back (Internet) - Make a call request via Internet (WIFI/GPRS/3G). You need at least 5KB to initiate the call.

Call Back (Autodialer) - Make a call request via our call back access number.

Call Back (SMS) - Make a call request via SMS.

Call Through - Make a call request via our call through access number.

Internet Call- Make a call request via Internet (WIFI/GPRS/3G). You won't receive callback anymore as the call gets through     directly. The rate is also cheaper compared to Callback (Internet). Data connection is needed for the entire duration of the call.

Tip: Call Back (Autodialer) and Call Through require no Internet connection, hence no data charges.