Could someone explain why we can’t just plug the average PC etc into a ‘raw’ internet line (like just entering a house) and have a mini modem on the motherboard do the translation work?
I know there’s a limit to IP addresses, and that it’s maybe easier to have a little box do the work where it enters a building.
… but apart from that?
So theoretically if you didn’t need more than one device at your end connected, you could (in theory) plug the internet cable straight into a pc. In theory.
Yes. In fact, that is what a server does. It is much like your PC, just heavily optimised for providing services (like websites) to many users. There is no modem between the server and the first router, just straight ip with the router as the default gateway.
You can. In practice
If you have two or more network adapters in your computer it can do network address translation to share your connection with your other devices that would use private IP addresses. If one of those network adapters is WiFi, your computer can act as a wireless access point.