According to VoIP and IM provider Gizmo, approximately 11% of landline and mobile telephones in the US are connected to a VoIP network somewhere along the carrier path. Thanks to a relatively new addition to Gizmo’s catalog of services, if you’re lucky enough to have any of your numbers fall into that 11% you can be called for free from anywhere in the world. The project page also includes a search box that allows you to quickly and easily determine whether or not a given phone number is eligible for backdoor dialing. Making use of the service is quite easy; just download the Gizmo5 to your PC / Mac / Linux computer and preface backdoor calls with 0101. The call will be absolutely free for both the caller and the recipient, and Gizmo claims that bypassing the PSTN leg of a connection will sometimes result in even better call quality than standard calling. Once you receive a backdoor call, you can also use the number displayed on caller ID to call back the Gizmo user any time for free! Perhaps the best part of the service is that it’s not tethered to the PC application. Users with compatible Nokia handsets can place backdoor calls using the Gizmo S60 app. In fact, Gizmo supports SIP so you should be able to setup your Gizmo account in any mobile or computer-based SIP client and enjoy backdoor calling. Gizmo states that their backdoor dialing program is experimental but good response might coax them into not only maintaining the service, but also broadening the scope. Definitely check it out; there’s no calling like free calling.
[Via atmaspheric endeavors]