I have a merlin system that I want to change. I think there is a way to change the cords in the jack to make them work with regular phones. Can anyone give me clear instructions about how to do this? Thanks so much... gail

If it uses the 8 conductors on Merlin, then I would remove all jacks, install a single or double jack for 1 or 2 lines.
Connect white/blue to green, blue/white to red, white/orange to black, and orange/white to yellow. Blue pair is line 1 and orange pair is line 2.
Then where the Merlin was, connect all of the white/blues together, and then the blue/whites together, and the orange pair, then connect to your 1,2 or more lines.