Does anyone know how they do this? Is this an internal database or something we can access?
Backdoor Dialing
Approximately 11% of US telephones, including mobile numbers and land lines from carriers such as Verizon, Sprint, T-Mobile, etc., are connected via VoIP. Working with telecom partners we are now making it possible to dial these numbers without going through the traditional phone system.
This means you can call certain mobile and land line numbers from any computer connected to the net and talk for free. Because these calls are bypassing the traditional phone network entirely there is no per minute fee or other charge for the caller regardless of where they call from.
http://gizmo5.com/pc/backdoor/
5. Why isn't my number part of the program?
Backdoor dialing is a new program. It is not available for every phone. Our estimates are that our connections give us coverage on approximately 11% of all phones in the US at launch. This includes landlines and mobile numbers from many carriers including Access One, Airadigm, Allegiance, Alltel, Cablevision Lightpath, Cat Communications, Cbeyond, Cellcom, Cellular Properties, Centennial Wireless, Choice One, Cincinnati Bell Wireless, Cinergy Communications, Cingular, CityNet, Cleveland Unlimited, Comcast Digital Voice, Commpartners, Conversent Communications, Cox Communications, CP Telecom, CTC Communications, Dobson Cell, Eureka, Globalcom, Heartland Communications, Illinois Valley, ITC Deltacom, LDMI, McLeod, Metro PCS, Mpower, Nationsline, Nextel, Nextera Communications, Paetec, RCN, Sprint PCS, Talk America, Telnet Worldwide, T-Mobile, US Cellular, Verizon Wireless, XO. The program is constantly being expanded.
Backdoor Dialing
Approximately 11% of US telephones, including mobile numbers and land lines from carriers such as Verizon, Sprint, T-Mobile, etc., are connected via VoIP. Working with telecom partners we are now making it possible to dial these numbers without going through the traditional phone system.
This means you can call certain mobile and land line numbers from any computer connected to the net and talk for free. Because these calls are bypassing the traditional phone network entirely there is no per minute fee or other charge for the caller regardless of where they call from.
http://gizmo5.com/pc/backdoor/
5. Why isn't my number part of the program?
Backdoor dialing is a new program. It is not available for every phone. Our estimates are that our connections give us coverage on approximately 11% of all phones in the US at launch. This includes landlines and mobile numbers from many carriers including Access One, Airadigm, Allegiance, Alltel, Cablevision Lightpath, Cat Communications, Cbeyond, Cellcom, Cellular Properties, Centennial Wireless, Choice One, Cincinnati Bell Wireless, Cinergy Communications, Cingular, CityNet, Cleveland Unlimited, Comcast Digital Voice, Commpartners, Conversent Communications, Cox Communications, CP Telecom, CTC Communications, Dobson Cell, Eureka, Globalcom, Heartland Communications, Illinois Valley, ITC Deltacom, LDMI, McLeod, Metro PCS, Mpower, Nationsline, Nextel, Nextera Communications, Paetec, RCN, Sprint PCS, Talk America, Telnet Worldwide, T-Mobile, US Cellular, Verizon Wireless, XO. The program is constantly being expanded.

