Can anyone clearify how to program a personal-COline to ring on a digital set/6408d once its assigned. Pers-COline is assigned will flash in but will not ring...this system has other lines working but customer would like this user to use it's assigned Co lines for incoming and out going only ...total of 8 co lines...all assigned to about 15 stations as pers-COlines. Currently they are not in a trunk group.