I has CXI and 4 analouge ls trunks, incoming calls picked by auto attendant , my problem is , if some one call and do enter ext and disconnect , the system does not sense for the disconnect , and call redirected to the operater to recieve empty call , but the big problem when there are no operater the trunk will stuck in busy for long time , so please help , why my system does not understand the exchange disconnect tone, exchange type is semines