Return Call service (also known as Call Back service) helps you save money on outgoing long distance phone calls when using your international cell phone abroad. Most wireless phone carriers around the world charge high airtime rates to make outgoing international phone calls from your cell phone, however they almost always offer free or cheap incoming call rates. Return Call service takes advantage of these low incoming call rates, to help you save money on your outgoing long distance calls.
When you sign up for Return Call service, you will be provided with a list of their local "Trigger Numbers" for every country around the world. When you are in your destination country, you can use your cell phone (with Local SIM card) to call the trigger number. A computer at the the Return Call service center will answer, and then you will simply hang up. A few moments later you will receive an incoming call from the Return Call service and be prompted to enter the Long Distance phone number that you would like to call.
Customer Support for Return Call Service is available in the USA by calling 1-703-533-2122 or by calling 1-800-705-5033 (in the United States only)