DAC - Digital addressable controller - This is the headend (media) component provided by arris (originally by Motorola). DNCS - Digital network control system - This is headend provided by Cisco (originally by Scientific Atlanta). These headend systems are responsible for managing STB's and subscriber database along with many other featured.

DAC - Digital addressable controller - This is the headend (media) component provided by arris (originally by Motorola). DNCS - Digital network control system - This is headend provided by Cisco (originally by Scientific Atlanta). These headend systems are responsible for managing STB's and subscriber database along with many other featured.

DAC is designed around the Motorola encryption keys and use only on Moto compatible STBs. DNCS is designed around PowerKey encryption keys and use only on SA compatible STBs.