Sorry telemarketing people :)

Like thousands of people in Portugal, I have a landline phone because we don't have any option to have Internet access without forcing us to have a damn(dumb) phone.
It was everything running fine until I started to receive annoying calls. Those pesky ISP people trying to increase my monthly bill with stupid promotions that neither I need or like (Stupid M4O).
Also, I don't even use the number on that PSTN line, just VoIP.
Why you may ask? Because my provider offers free landline calls between 9pm and 9am, however, on VoIP (their own service) don't have this kind of limitation, go figure...
You may say: "Just disconnect the phone", well, ok, but this wouldn't be a smart option.
Having a spare Raspberry the work began.

• Purchased a Linksys SPA-3102 and attached it to the landline
• Setup and configured FreePBX @ Raspberry Pi
• Setup inbound and outbound rules like this:

All the calls incoming from the landline (SPA) will receive music on hold as long as the call lasts.
Add an exception to my own number, so that I can call home in case of emergency.
Add outbound route to direct all the outgoing calls via VoIP provider.
Add rule (with prefix) to allow outgoing via PSTN in case of VoIP failure.
Add rule to emergency calls (112); It will terminate any call in progress and route it through PSTN.

So, now I can eat, sleep and be with my family without having to answer dumb telemarketers.
It took about half an hour to accomplish this and another half to put everything in place.
Sorry MEO guys, but your promotions suck...