Cable Service: –
Cable television programming is often divided between basic and Pay TV or premium programming. Basic cable TV networks are generally transmitted without any television encryption or other scrambling methods and thus anyone connected to the cable TV system can receive the basic channel. Most systems use hybrid fiber coaxial (HFC) distribution; this means the trunk lines that carry the signal from the head end to local neighborhoods are optical fiber to provide greater bandwidth and also extra capacity for future expansion. At the head end the radio frequency electrical signal carrying all the channels is modulated on a light beam and sent through the fiber. The fiber trunk line goes to several distribution hubs, from which multiple fibers fan out to carry the signal to boxes called optical nodes in local communities. At the optical node, the light beam from the fiber is translated back to an electrical signal and carried by cable distribution lines on utility poles, from which cables branch out to subscriber residences.