57.7.9.5.4 Header Transmission

Each LON frame, after sending the preamble, starts with the frame header also called L2HDR according to CEA-709 specification. This header consist of the priority bit, the alternative path bit and the backlog increment. It is the first data to be sent.

In LON mode, the transmitting algorithm starts when FLEX_US_LONL2HDR is written (it is the first data to send).