US Patent 7965646 Wireless code-passing system for stateful connection monitoring

A stateful connection is monitored between wireless communications devices. A first code packet is generated at a first wireless communications device. The first code packet is transmitted from the first wireless communications device to a second o wireless communications device. A determination is made whether a second code packet generated by the second wireless communications device in response to receipt of the first code packet is received by the first wireless communications device within a predetermined time.