I have few projects ideas that involve plugging a computer or an arduino to my landline phone (or just before it). For example, I would like to grab the caller ID sent when someone calls, do a lookup on the web or in an address book, and display the associated name on a LED screen.
The problem is that I can't find any resources on the protocols used for transmitting this caller ID, etc. I may have misused my google skills, so could anyone give me some pointers ?
I am particularly interested in all the protocols evolving around landline phones (caller ID forwarding/blocking, sending SMS, starting/ending a call, etc.). It is my understanding that while the long distance part (from central to central) is numeric, the signal reaching the phone on the customer side is still analogic. Is it true ?