Virtual Channel

Virtual channel 1 In most telecommunications organizations, a 'virtual channel', is a method of remapping the program number as used in H.222 Program Association Tables and Program Mapping Tables to a channel number that can be entered via digits on a receiver's remote controller.

Virtual channel 1 A virtual channel was first used for DigiCipher 2 in North America and then later used and referred to as a 'logical channel number' (LCN) for private European Digital Video Broadcasting|DVB extensions widely used by the NDS Group and [ NorDig] in other markets.

Virtual channel - Implementation 1 The DigiCipher 2 method uses a privately defined 'virtual channel table' (VCT) to set the channels major and minor numbers that appear on-screen separated by a decimal point. The major number for ATSC represents the original analog or non- simulcast channel frequency while the minor is a sequentially assigned number for the selected channel with zero reserved for the analog channel. The channel may also be marked as hidden from the viewer.

Virtual channel - North America 1 Most stations in the United States follow the ATSC numbering guidelines; however, there are some exceptions for low-power stations such as New York City's WNYZ- LP, which broadcasts on VHF channel 6 in digital, but uses the virtual channel 1.1, instead of 6.

Virtual channel - North America 1 The assignment of virtual channels in the United States is defined within the stream via terrestrial or cable versions of a Virtual Channel Table as outlined by ATSC document A/65, Annex B. Rules for assignment of major channel numbers are as follows:

Virtual channel - North America 1 *The real numbers of stations that are using virtual channels from 52 to 69 (these stations are not covered by the reciprocity rule, as real station numbers are not assigned above 51)

Virtual channel - Europe, Africa and the Middle East 1 In continental and eastern Europe, virtual channels are not used, since television sets and receivers there allow users to freely assign arbitrary programme numbers or programme letters to channels.

Virtual channel - Europe, Africa and the Middle East 1 Virtual channels are also used on direct broadcast satellites, such as Dish Network, DirecTV, and SES Astra|Astra. Rather than a few dozen channels with a few subchannels each, these services map to a range of hundreds of individually numbered channels. This is true of digital cable and satellite radio services, as well.

Virtual channel - Japan 1 Current standards allow for a maximum of eight virtual channels per broadcaster (in this example ).

Virtual channel - Japan 1 Additional datacasting services use virtual channels in the 200–799 range – in this example, the network could use the 22x, 42x and 62x ranges.

Virtual channel - Philippines 1 As the Philippines started its transition to digital terrestrial television back in 2008, virtual channels have been tentatively assigned to TV networks who are now in operation. In June 2010, the National Telecommunications Commission finally adopted ISDB-T as the sole digital terrestrial television standard in the country.

Virtual channel - Digital radio 1 In-band on-channel|IBOC system (Digital Radio Mondiale) stations do not currently use any virtual channels because of the limited bandwidth available in analog sidebands.

Virtual Channel identifier - Why virtual circuits? 1 Every ATM cell has an 8- or 12-bit 'Virtual Path Identifier' (VPI) and 16-bit 'Virtual Channel Identifier' (VCI) pair defined in its header.Cisco Systems [ roduct/atm/c8540/12_1/pereg_1/atm_tech/ techgd.pdf Guide to ATM Technology] (2000)

Virtual Channel identifier - Why virtual circuits? 1 ATM switches use the VPI/VCI fields to identify the Virtual Channel Link (VCL) of the next network that a cell needs to transit on its way to its final destination

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