Asterisk SIP to PSTN


I have a question I hope someone can help me get the answer to. I’m on my way to setup a own gsm-base station using a USRP together with openBTS and Asterisk. The idea is that my phone will connect to this short-range base station when making a call and make this phone call be a SIP-call handled by Asterisk. From the documentation of the different parts it looks like this should work without problem.
But I also want to be able to call landline phones/mobile phones with this equipment. I do not want to insert a pstn-card into the asterisk server. I have been thinking about letting the outgoing SIP-call go to a SIP-gateway and from there be redirected out to the PSTN network. What I have understood will this work. Anyone know if this is right?

I was hoping for that I do not must set up the SIP-gateway myself and instead connect to some SIP<->PSTN service provider. I guess this will cost some amount of money for calls but that is not a issue. So my question is if this is possible to do with Asterisk, and if so, do anyone know what service providers that can be used? I’m living in sweden but it doesn’t matter where the service provider is located as long as I can call from sweden to sweden.

This is for a research project that I’m participating in at the University. I reliaze that this might not be the best way to do it but this is the way the project is supposted to be configured (if possible).

Thanks for all answers! :smile:

try googling sweden sip provider.