When the node application has data to send to the hub the node transmits a DATA packet and listens for an AutoACK. If an AutoACK is not received, the node retransmits the packet. If the node does not receive an AutoACK after n DATA_PACKETS_RETRIES of retransmissions of the data packet it assumes the hub has changed channels and then enters node ping mode. If the node still fails to contact the hub, it assumes the channel has become unavailable due to excessive interference and goes to connect mode timeout. The packet to be transmitted is held until the node ping or connect is successful and then transmitted. Transmit data packets are never discarded.