In telecommunications, a logical channel number (LCN), also known as virtual channel as used in ATSC SI data, is a channel designation which differs from that of the actual radio channel (or range of frequencies) on which the signal travels.
The term is most often applied to television, where digital television (DTV) channels may operate on different physical channels from the displayed channels. A station branded as Channel 8, for example, might actually use channel 32 for its ATSC, DVB or ISDB transmission, but a virtual channel map or virtual channel table (VCT) allows viewers to tune in the station on channel 8, displayed as 8.1 on a digital set. DTV tuners have a menu item that scans all channels for this information and stores it in memory for instant access later on.
The most common reason for a television station using a virtual channel is to minimize viewer confusion when a digital transmission is airing on a different channel from the one the station used in analog mode. The virtual channel thus enables viewers to tune in the station by choosing the same channel number as they would have previously. In the case of pay TV and joint broadcaster services such as Freeview the channel number is also a way of locking in the ordering of channels to an order that suits the provider rather than to what the viewer may prefer.
Famous quotes containing the words virtual and/or channel:
“Tragedy dramatizes human life as potentiality and fulfillment. Its virtual future, or Destiny, is therefore quite different from that created in comedy. Comic Destiny is Fortunewhat the world will bring, and the man will take or miss, encounter or escape; tragic Destiny is what the man brings, and the world will demand of him. That is his Fate.”
—Susanne K. Langer (18951985)
“... the modern drama, operating through the double channel of dramatist and interpreter, affecting as it does both mind and heart, is the strongest force in developing social discontent, swelling the powerful tide of unrest that sweeps onward and over the dam of ignorance, prejudice, and superstition.”
—Emma Goldman (18691940)