Identify 865-1057 Network Power Supply and 809-0903 Network Tee
These two parts look almost identical externally. In fact the 865-1057 uses the same plastic enclosure. See the attached picture.
The 809-0903 is a Xanbus network Tee and the 865-1057 is a Xanbus Network Power Supply (12VDC@1.5A). They are related because they both may be used in Xanbus network systems. The Tee (809-0903) is rarely used because 99.9% of people install daisy chain networks which do not require the Tee. It is tailored towards the RS/MS inverters, but it is still Xanbus, the network gets installed identically and is a smaller document than the XW installation guide. The 865-1057 is designed to power a Gateway, but can also be used in any application where there are no network power supplies (XW Inverter/Charger). If a customer wants to use and XW MPPT controller and SCP without an inverter, this would be the part that he wants.