head-end controller 
Also known as a cable modem termination system (CMTS), a head-end controller device provides access to the Internet over a cable network by connecting to an IP router that sends and receives the data from the rest of the Internet. The controller interprets the data it receives from individual customers and keeps track of the services offered to each of them. The controller also modulates the data received from the Internet so that the head-end equipment can send it to a specific subscriber.