It looks like the ONT and the BBU are one integrated unit. Did the old ONT was outside or inside?
The old one was outside. This one is inside
Some ONTs are inside only. An outside ONT can also be installed inside, although an inside ONT is usually used.»Verizon Online FiOS FAQ »What are the different models of ONTs?--There are 10 kinds of people in the world; those who understand binary and those who don't.
Not great pix but...hope that helps.