We find the cheapest route to call any telephone number. No configuration to maintain. No special extensions. Uses any VoIP technology. And yes, it's free. Interested?
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So you have a client who has two offices: one in location A and one in location B. To let them save on their telephone bill, you set up a VoIP trunk from server A to server B: every time they dial the number of office B, it is called via VoIP, and when they call site A from B, it is called via VoIP. Pretty cool.
Then your client adds a new office C: you add a rule each to server A and B to call C over VoIP; and add two rules on C to call A and B. And you're done.
Then your client closes office B and opens a new office D: again you have to change the routes on all PBXs involved. But I am sure you start to see a pattern here.
With Fone-U, there is no configuration to maintain: calls automatically flow using the cheapest route. and if no route is available, they simply use the public network.
You know how it is: calling mobile phones is quite expensive. In some countries the extra cost is paid by the caller, in other ones it is the callee who has to pay the price difference. As many users today have smart phones with data plans, it would be simpler and cheaper to simply call them over VoIP.
But some have a SIP client; others prefer Skype or Google Talk. So you need to keep a list of aliases for each of them: their telephone numbers plus a VoIP route for each of them. If you have one or two, it is very easy. If you have 50, it starts to look like a nightmare.
With Fone-U, calls to any mobile flow using the VoIP client of choice: use SIP, IAX or proprietary - it's up to you.