It connects the calls from the mobile phone to the Packet8 digital VoIP network to save on costs.
Packet8 MobileTalk users can dial calls directly and natively from their mobile handset, contact list or speed dial directory. Once the destination number is dialed or selected, the Packet8 MobileTalk software application identifies the international prefix being called and redirects the call to a local Packet8 network access number for terminating the last leg.
You might say Packet8 MobileTalk is similar to Truphone, except Truphone routes the call over the data connection, so the QoS is more affected. You might compare Packet8 MobileTalk with JAJAH, which offers the JAJAH Mobile Plugin, a softphone application that like MobileTalk works with Symbian phones. JAJAH Mobile Plugin, like Packet8 MobileTalk routes the call over the voice channel. However, JAJAH Mobile Plugin differs in that it only works with Symbian phones right now I believe and not Windows Mobile devices. Still, this is probably the closest comparison and it puts Packet8 in direct competition with JAJAH. Still... it's hard to compete with JAJAH's free global calling plan, but I give Packet8 credit for differentiating themselves.
Interestingly, with Packet8 MobileTalk, all calls are carried to the Packet8 network over the subscriber's existing cellular voice phone service. That is, you don't need a data plan as the voice is routed directly over the cellular voice channel to Packet8's servers. In this way, the call quality should be excellent.
Importantly, customers do not have to subscribe to other Packet8 VoIP or videophone services in order to sign up for Packet8 MobileTalk, though discounted service fees are offered to existing Packet8 VoIP or MobileTalk subscribers. There is a one-time $9.99 activation fee for the service and a monthly fee of $9.99 for non-Packet 8 subscribers. Existing Packet8 VoIP subscribers, including subscribers with one Packet8 MobileTalk account, pay a monthly service fee of $4.99.
You can check out and download the Packet8 MobileTalk here: http://mobiletalk.packet8.net