I feel there should be a setting in the FIOS box to select the sound output to the optical port for the soundbar. Since it is a digital soundbar, optical is the only way to connect it. There are active converters to convert an analogue output to the digital signal, but most need to be connected to a pc while being used, making them impractical. Stand-alone ones might exist, but would probably we worth more than its worth to get them for your setup.