UTEK UT-211 Port-powered RS-232 to RS-232 Mini-size PhotoElectric Isolator

This product is supposed to take power from the RS232 port. It does not work.Sellers reply to my question why does this not work"I contacted a colleague from the factory technical department. He said that the UT-211 product needs to be powered by the serial COM interface. Your scene cannot be powered, so it cannot be used. He recommends that you use the UT-2112, which is powered externally."I have requested a refund.