DALI protocol is a half-duplex digital communication composed of forward and
backward frames, and it uses the bi-phase Manchester asynchronous serial data format. The convention of Manchester coding specified by IEEE is that a logic '0' is represented by a High-Low signal sequence,
and a logic '1' is represented by a Low-High signal sequence.
The data transition rate is 1200 bit/sec, and thus the bit period is 833 micro second.
A DALI transmission consists of 2 types of message frames, namely, forward frame (sent by a controller) and
backward frame (answered by a luminaire/device). The backward frame will only be answered, if the forward
frame includes a command which queries the luminaire/device. The response time of
luminaire/device to a
query commanded by a forward frame is between 2.92 milliseconds and 9.71 milliseconds.