One of the great things about a Pelco Spectra dome system is the ability to add components as needed without having to purchase a whole new system. The Pelco FS85011SST is a fiber optic transmission board specifically designed for installation inside a Spectra III series back box. With this card in place, you'll be able to send pristine quality video along with bidirectional RS-422 and Coaxitron control signals over fiber optic. When compared to copper-based cables (i.e. BNC, RCA, UTP), fiber optic suffers very little signal attenuation and is completely immune to electromagnetic interference. It is also virtually impossible to illicitly tap into a fiber cable in the way that can be done with metal-based cables. What all this means to you is that you'll get to send large amounts of data, over long distances, and in a secure manner.
This board can also be used with an ExSite explosion proof positioning system, but requires installation at the Pelco factory.