Patent ID: 9634863
Date: 2017-04-25
CPC Classifications: H04L

Claim:
1. A slave device comprising: an upstream network connection port; a downstream network connection port; a field bus logic module coupled to the upstream and downstream network connection ports adapted to process field bus packets that are formatted, above a physical protocol layer, with a time sensitive protocol; a microcontroller coupled to the field bus logic module adapted to process packets of a second type that are formatted, above a physical protocol layer, with a non-time-sensitive protocol; logic circuitry adapted to receive packet data and to selectively tag a preamble of a packet to indicate that is a packet of the second type; logic circuitry adapted to selectively remove the tag from the preamble of a packet; a first packet filter coupled between the field bus logic module and the upstream and downstream network connection ports, the first packet filter is configured to a second packet filter coupled between the downstream network connection port and the microcontroller, wherein the second filter is configured to wherein the first and second packet filters distinguish packets formatted with a non-time-sensitive protocol by inspecting tags inserted into the preamble of the packet; and a third packet filter coupled between the downstream and upstream network connection ports of the slave device, wherein the third packet filter is configured to modify the value in the preamble of the second type of packet received from the downstream network connection port of the slave device; wherein the first and second packet filters are configured to filter packets based on a value in a header of (1) the field bus packets or (2) the second type of packet, wherein the value is in an Ethertype field of the header of the field bus packets or the second type of packet; and wherein the first and second packet filters are configured to filter packets based on a value in a preamble of (1) the field bus packets or (2) the second type of packet.