My experience in trying to reproduce one of these rotary VoIP write-ups that make the front page is that the authors tend to leave out some critical piece of their network/general setup that would allow others to reproduce. So in the end, good, interesting write ups but your mileage may vary in trying to reproduce.
Using the VoIP credentials of my ISP in the Fritz!Box or ATA and nothing else. (which they must provide since The Netherlands has free modem choice: https://web.archive.org/web/20230921231725/https://www.acm.n...), no other setup involved, no port forwarding, etc.
As the author of a different VoIP write-up that made the front page, you're not wrong. There's a lot of variance across home networks, and SIP behind a NAT can be incredibly painful to get working correctly.
If you can build a PC or configure a consumer router, you can set up an ATA. Just make sure to buy the right ATA (one that supports pulse dial). Then find a half-way decent VoIP provider.
