We have an AT&T SB67118 four line phone with two cordless handsets, we went to put a third line in it and it won't break dial tone when we try to call out. I can't find any settings on tone or pulse options in the manual. The line itself is fine since we changed it out with line one and it would dial out. Lines one and two are ok and have been working for over a year. Unplugged it for a couple of minutes with the batteries removed and still no go...pulling the last strands of my hair out as we speak.....