Mobile VoIP Provider

Mobile VoIP providers offer one of the newest and most exciting applications of VoIP technology: Mobile VoIP. With the recent explosion in Wireless Internet (better known as Wi-Fi) and powerful smartphones that use 3G connections, mobile use of VoIP phones has become much easier to come by. Mobile VoIP providers offer two basic types of service, based on how the VoIP service is run: software-based mobile VoIP (which can allow you to connect via cellular phone to a VoIP provider's network) or hardware-based mobile VoIP.
Software-based Mobile VoIP: Softswitch

Software-based Mobile VoIP providers use softswitch software to route VoIP calls. "Softswitch" refers to the software that the phone companies and VoIP providers both use to route the calls. With the mobile VoIP software that VoIP providers offer for download, you get a more compact version of that software. The software redirects you to the other person, if they're on the same software network. Otherwise, the software redirects you to the mobile VoIP provider's own softswitch, which sends the call off to the public network – that is, to the caller.

Software-based Mobile VoIP providers rarely, if ever, charge for calls within their network. Usually, they have a debit-based system: you deposit a certain amount of money to your account and they charge that account for the off-network calls you make. Remember, calls within the network are free.

Since software-based mobile VoIP providers can be downloaded, they run on computers around the world and smartphones. As 3G coverage improves, 4G connections bring faster connection speeds, and Wi-Fi hotspots increase, mobile VoIP software will become more and more widely-used. TerraSip is one of the best of these software-based mobile VoIP providers, but trust us, there will be more in the future.
Hardware-based Mobile VoIP: Bring your own phone.

We're far enough down the page. We can let you in on a secret (well, sort of):

Most IP phones "work" as mobile VoIP devices. Since they are frequently provided and programmed to work with the VoIP provider managing your system, you can unplug them and take them anywhere. The number will still be the same (since it is registered to your phone). Literally, you can just take your phone with you. It's one of the reasons why virtual numbers are so valuable.