It’s great to get cheap or even free calls through VoIP. But it’s even better if you can route calls to and from your mobile phone. This way you can go around those costly long-distance and international rates when calling from your mobile.

The MV-370 gateway is manufactured by Portech and will cost you only $150. Aside from being affordable, what’s great with the MV-370 is that it bridges GSM directly with SIP, and it’s not a GSM to FXS (meaning an adaptor that bridges mobile calls to PSTN). This means it connects directly to your VoIP gateway via the local area network.

The MV-370 uses its own GSM subscriber identitiy module (SIM) card, and therefore has its own telephone number. The typical setup would be for the MV-370 to be connected to your local area network, to which your Asterisk gateway is also connected. You just call the MV-370′s phone number, and it gives you an access dial tone. Just dial the desired destination phone number, and Asterisk takes care of connecting to the claled party via your VoIP provider.

The benefits? In some instances, calling a number directly from your mobile phone might be cheaper than having to call home to your GSM-to-Asterisk gateway. However, using a GSM gateway would be ideal in these instances: First, if your mobile network has “family” calling plans, which lets you call certain numbers for lower tarrifs, or even for free. Second, if you’re calling overseas, then calling through VoIP can definitely be cheaper. Third, using a GSM gateway adds in mobility. Say you run an office, and you use Asterisk as your VoIP gateway. You can then have calls made to your office trunk line routed to the mobile phones of your employees–very useful when on the field or when telecommuting!

The MV-370 comes with substandard documentation, though. VoIP info has a walkthrough for setting up the gateway with Asterisk.