... 11 messages at one time, 1 message will be displayed and up to 9 messages will be stored, the queue (stored messages) ... requests need to be responded, the manager will knows the guests' service request speed, and staff efficiency 2) 'Request-Confirm-Respond' work ... a request message is displayed, which a waiter confirm to respond to will be deleted, and the other waiters can avoid useless overlapping ...