Ok so I inspected all 3 smoke detector and this is what I found. Each smoke detector as 3 wires coming out of it (red-black-orange) and connected as follows:
1- Basement is connected: Black wire with 2 other blacks, white with 2 other white and the orange with 1 red
2- Main floor is connected: Black with 2 other blacks, white with 2 other white and the orange with 2 reds
3- 3rd floor is connected: Black with 3 blacks. white with 3 whites and orange with 1 red.
If my unexperience knowledge is right, the one in the basement is bring current to the main floor smoke detector by the red cable and the 2nd floor is feeding the 3rd floor this is whu the main floor detector is the only one with 2 reds.
Now my question is, if I have 3 wire coming out of the smoke detector is it right to say I have a 2 wire system? However I do have 4 wire going to the ELK panel. Should I be using the 2 way method to connect the elk? Hope Im getting somewhere