Ethernet network device comprising: - at least one host having at least one transmission port and at least one reception port, - a plurality of slave devices comprising at least one first and one last slave devices (3a, 3b), each slave device having: • a physical device or PHY-chip, particularly only one physical device or PHY-chip, having at least one respective reception port and at least one respective transmission port; • at least one integrated device, particularly of the programmable type, connected to the physical device, optionally by at least one MII or RMII converter; - at least one circuit on which the host and slave devices are active, said circuit having at least one main data sending line directly connected, on one side, to the host transmission port and, on the other side, directly connected to the first slave device reception port, said circuit further having one main data receiving line directly connected, on one side, to the host reception port and, on the other side, connected to the transmission port of the last slave device, said circuit further having at least one interconnection line connected, on one side, to the transmission port of one slave device, and on the other side, directly connected to the reception port of one slave device consecutive according to a data transmission direction to define a series connection between the slave devices, characterized in that the slave devices have a same MAC address which is set in each integrated device, so that the integrated device of each of said slave device is configured for receiving a data packet having said MAC address, each integrated device being configured for: - receiving at least one data packet according to an Ethernet protocol, said data packet being of the type comprising at least one preamble, at least one receiver MAC address, at least one source MAC address, a field identifying the used protocol type, at least one payload field, one cyclical redundancy control field, - reading at least part of the contents of the payload, - withdrawing at least a part of the payload data containing the information destined to the slave device itself, - modifying at least part of the data contained in the payload and/or data from the cyclical redundancy control field, - simultaneously with the withdrawal of at least a part of the payload data, modifying at least a part of the data inside the payload itself of the data packet itself. - at least one host having at least one transmission port and at least one reception port, - a plurality of slave devices comprising at least one first and one last slave devices (3a, 3b), each slave device having: • a physical device or PHY-chip, particularly only one physical device or PHY-chip, having at least one respective reception port and at least one respective transmission port; • at least one integrated device, particularly of the programmable type, connected to the physical device, optionally by at least one MII or RMII converter; • a physical device or PHY-chip, particularly only one physical device or PHY-chip, having at least one respective reception port and at least one respective transmission port; • at least one integrated device, particularly of the programmable type, connected to the physical device, optionally by at least one MII or RMII converter; - at least one circuit on which the host and slave devices are active, said circuit having at least one main data sending line directly connected, on one side, to the host transmission port and, on the other side, directly connected to the first slave device reception port, said circuit further having one main data receiving line directly connected, on one side, to the host reception port and, on the other side, connected to the transmission port of the last slave device, said circuit further having at least one interconnection line connected, on one side, to the transmission port of one slave device, and on the other side, directly connected to the reception port of one slave device consecutive according to a data transmission direction to define a series connection between the slave devices, characterized in that the slave devices have a same MAC address which is set in each integrated device, so that the integrated device of each of said slave device is configured for receiving a data packet having said MAC address, each integrated device being configured for: - receiving at least one data packet according to an Ethernet protocol, said data packet being of the type comprising at least one preamble, at least one receiver MAC address, at least one source MAC address, a field identifying the used protocol type, at least one payload field, one cyclical redundancy control field, - reading at least part of the contents of the payload, - withdrawing at least a part of the payload data containing the information destined to the slave device itself, - modifying at least part of the data contained in the payload and/or data from the cyclical redundancy control field, - simultaneously with the withdrawal of at least a part of the payload data, modifying at least a part of the data inside the payload itself of the data packet itself.