Rotary Phone

[Sebastian Harder]

Not exactly revolutionary but I want to take my old rotary phone and enable

1. button depress on rotary phone hangs up cell phone

2. dialer works

3. phone is plugged in via micro usb and charges while it is connected

Does this sound possible?  Where do I start?  How do I send a command from the rotary phone to the arduino and to the cell phone?  

Any ideas?

I'd prefer not to use bluetooth for simplicity and also so the cell charges.