On a channel by channel basis, the protocol supports optional priority. Priority slots, if any, follow immediately after the Beta1 period that follows the transmission of a packet (see Figure 1). The number of priority slots per channel ranges from 0 to 127.
The number of priority slots in the LON network configuration is defined through the PSNB field of the USART LON Priority register (US_LONPRIO). And the priority slot affected to the LON node, if any, is defined through US_LONPRIO.NPS.