I have an older merling legend system (4 years old). I have added an expansion cabinet with (1) 8 line module. Ever since, customer dials 9, sometimes it doesn't register. Mw lights don't turn off and calls bypass direct extension transfer and go to operator. I have done touch tone rec. tests and found that out of 16 ttr they all work about 60 - 70% of the time. I have tried installing a new 8 line module no help. I have the system set up for 2 differnet business. One dials 8 and the other 9. any insite?