Eurotech Appliances An0038 Ethernet physical adapter Versions, EurotechCODE, Description, RTL8139

10 Application Note

Important Note. Connection to a 100BASE-TX hub for 100 Mbps operation requires Cat. 5 Unshielded Twisted-Pair (UTP) cable or Cat. 5 Shielded Twisted-Pair (STP) cable. The maximum length between the 100BASE-TX hub and the adapter is 100 meters. Connection to a 10BASE-T hub for 10 Mbps operation requires a Cat. 3, 4, 5 UTP cable or Cat. 5 STP cable. Preferred maximum cable length between CPU-1220 module and Ethernet adapter is 10 cm (4”)

Ethernet physical adapter Versions

This physical adapter is available in two different versions:

	Table 4. Physical Adapter code
EurotechCODE	Description	Valid for
		RTL8139
ACS-9071-00	RJ45 ETHERNET ADAPTER FOR CPU-1220 AND CPU-1231	B
ACS-9071-03	RJ45 Ethernet adapter for CPU-1232 and CPU-1220	C

Warning: To prevent incorrect data transmissions select the proper physical adapter device depending on the Realtek RTL8139 chipset installed on the CPU-1220.

Integration of the Ethernet physical adapter

If the Ethernet physical adapter has to be integrated over a custom circuitry, please refer to Eurotech for detailed information about schematics.

Regarding schematics, a good choice is isolating the Ethernet adapter section from the rest of the power supply section. Derive the supply directly from the J4 Ethernet Connector of the CPU-1220. In this way if different versions of Realtek RTL8139 chipsets are installed no damage occurs when you connect J4 to the carrier board.

Warning: please take care on the Realtek RTL8139 version used in order to avoid short-circuits between +5V and +3.3V when deriving power supply.