Got inspired by someone asking how to read caller id with arduino. I wonder if anyone has hacked a caller id box as a project box. See, it's got a decent display, a few buttons, and at least a power jack and two phone connectors for connecting to stuff. Some may even have a battery backup. I don't own a land line or a caller id box. Anyone with experience?
Darn it. But if someone could mass-make DIY project boxes with a display, a few buttons, and a power jack, they could make some money :)
No experience with caller-id personally, but I do know that the actual information is transmitted between the first and second ring of the phone; or at least, that's the way it was with a land line back in the 1990s.
Your best bet to find out more about this is to look up "caller ID phreaking"; here's a sample of what you'll run into:
You'll find a lot of text files and such from the "underground", because that's where the interesting information on caller ID is. Note that a lot of this stuff is from the perspective of using and abusing the information for quasi-legal to completely illegal hacking purposes; use this information wisely.
You can also look up "caller ID decoding"; an example page:
There are tons of pages and info out there on playing with this; I am sure it can be easily done with an Arduino.
Here's another thread that might interest you: