Hybrid fiber-coaxial
Hybrid fiber-coaxial (HFC) is a broadband telecommunications network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s.
In a hybrid fiber-coaxial cable system, television channels are sent from the cable system's distribution facility, the headend, to local communities through optical fiber subscriber lines. At the local community, an optical node translates the signal from a light beam to radio frequency (RF), and sends it over coaxial cable lines for distribution to subscriber residences. The fiber optic trunk lines provide enough bandwidth to allow additional bandwidth-intensive services such as cable internet access through DOCSIS. Bandwidth is shared among users of an HFC. Encryption is used to prevent eavesdropping. Customers are grouped into service groups, which are groups of customers that share bandwidth among each other since they use the same RF channels to communicate with the company.