... be widely used in the restaurant, game hall, pub, night club, TV..Where have the waiter, you can instill ... work with all the transmitter as the picture showed 2.Installation : install the Y-500/485 on the wall , ... you on 001 table press the "service " key on the Y-F4L-C ,The Y-500/485 will show ... "service ". what is more different indicator on the receiver in stand of different services ,say one ...