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VOIP has caught my interest today as it seems to be a great solution for somebody who travels frequently and needs to make cheap/free calls from wherever.

I know I can setup my own PBX server with something like Asterisk, but where I am getting hung up at is the service itself. A lot of the documentation out on the web states that you need both the VOIP PBX AND a subscription to a VOIP provider (For a VOIP phone number).

Isn't setting up an Asterisk box essentially providing the VOIP service yourself? Is the VOIP subscription just for the phone number?

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up vote 0 down vote accepted

Correct. As long as the client knows the IP address of the PBX it can connect. VoIP providers usually provide PSTN connectivity.

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So basically I can make VOIP to VOIP calls for absolutely free but if I wanted to call a cell phone or a land line I would need a VOIP provider? – Scandalist Jan 16 '13 at 9:35
Or if you wanted a land line or cell phone to be able to call in; PSTN connectivity is usually bidirectional. – Ignacio Vazquez-Abrams Jan 16 '13 at 9:36

A lot of technologies have changed since. Today, you don't need a VoIP PBX at all if you subscribe to a cloud based VoIP phone systems. In reality, if you have a data plan on your mobile phone, you can make and receive calls from anywhere and any time.

Even some parts of Unified Communications ( are available on the mobile phone with fantastic applications that can be downloaded and used on Android, and iOS.

Just take a look at all the cloud based services available today.


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