The BBU provides power for the ONT. Fiber optic cable does not support sending power where the old copper wire that carried phone service before did. Therefore, the BBU and PS together provide power to the ONT. While you may not technically need the BBU in a power outage (since you are not using the phone) I am not sure that it is possible to connect the PS directly to the ONT.
Written by Ron-fiosFAQ
Last updated on 02.15.07