EDIT: On hindsight, I think my original post was a bit ambiguous.
What I actually want to know is how the circuit board is controlling the LCD (what inputs it is sending to the LCD and so on). So in order to know that, I need to find out what each of the pins does.
I put it up to the light and I could read from a hand "• DN" and the other "D1352" written, but still did not find the datasheet. There is some code to search for it?
Listen to the advice from LarryD. It's a custom ASIC - you will never be able to use it unless you can have the arduino emulate a phone central and line.