When the visual feedback is associated with a ZBRT1 transmitter and the button is pressed the visual feedback will flash 2 times. (30ms on, 30ms off, 30ms on). When the visual feedback is associated with a ZBRT2 transmitter and the button is pressed the visual feedback will flash 2 times and then flash 2 times when the button is released. The difference is only between the kind of transmitter as you can see not linked with the receivers.