if you have a 1n4004 diode you can put it across the line. in one direction it kills the dialpad, in the other it does not.
there is a lead that when pulled kills dt, put it back on the dial pad in another location and dt comes back but the dial is dead, since dt is in series with those leads. i want to say you pull the black lead and put it back down with the blue.
john poole
bellsouth business
columbia,sc