DC plug for Telus ONT box??

I currently have a UPS battery backup system powering my Telus modem and ONT box. However in order to free up more space and save energy I need to switch to a DC-only UPS system. For the Telus modem this is no problem as it uses a standard 5.5mm DC barrel plug.

But what power plug does the ONT box use?! It is a rectangular plug and looks unconventional. Does anyone know the name of this plug so I can find an adapter online? Or does Telus offer other ONT boxes that have more standard DC plugs (or better yet powered by USB)?