DigiCipher 2

DigiCipher 2, or simply DCII, is the name of the digital signal compression standard used on many communications satellite television and audio signals. The DCII standard was originally developed in 1997 by General Instruments, which is now the broadband division of Motorola.

The original attempt for a North American digital signal encryption and compression standard was DigiCipher 1, which was used most notably in the now-defunct PrimeStar medium-power DBS system during the early 1990s. The DCII standard predates DVB-based digital television compression and therefore is incompatible with the DVB standard.

The primary difference between DigiCipher 2 and DVB lies in how each standard handles SI, or System Information. DigiCipher 2 also relies on the fact that its signals must be understood in terms of a virtual channel number in addition to the DCII signal's downlink frequency, whereas DVB signals have no virtual channel number.

Approximately 70% of newer first-generation digital cable networks in North America use the 4DTV/DigiCipher 2 format. The use of DCII is most prevalent in North American digital cable television set-top boxes. DCII is also used on Motorola's 4DTV digital satellite receiver and StarChoice's DBS receiver (StarChoice is based in Canada).

External links

• Good technical page on digital satellite signals (http://www.coolstf.com/mpeg/)