Datacasting

Datacasting (data broadcasting) is the transmission of data over a wide area using radio waves. It typically refers to supplemental information sent by television stations alongside digital terrestrial television (DTT) signals. However, datacasting can also be applied to digital data signals carried on analog TV or radio broadcasts.

Datacasting (data broadcasting) is the transmission of data over a wide area using radio waves. It typically refers to supplemental information sent by television stations alongside digital terrestrial television (DTT) signals. However, datacasting can also be applied to digital data signals carried on analog TV or radio broadcasts. ==Datacasting services around the world== ===North America=== ====Ambient Information Network==== Ambient Information Network, a datacasting network owned by Ambient Devices presently hosted by U.S.A. Mobility, a U.S. paging service which focuses on information of interest to the local (or larger) area, such as weather and stock indices, and personalized information will be provided with a paid ambient subscription on that particular device. ====RBDS==== A slight variation of the European Radio Data System, RBDS is carried on a 57 kHz subcarrier on FM radio stations. While originally intended for program-associated data, it can also be used for datacasting purposes including paging and dGPS. ====DirectBand==== DirectBand, owned by Microsoft, uses the 67.65 kHz subcarrier leased from FM radio stations. This subcarrier delivers about 12 kbit/s (net after error correction) of data per station, for over 100 MB per day per city. Data includes traffic, sports, weather, stocks, news, movie times, calendar appointments, and local time. ====MovieBeam==== The now-defunct MovieBeam service used dNTSC technology by Dotcast to transmit 720p HDTV movies in the lower vestigial sideband of NTSC analog TV. The set-top box stored the movies to be viewed on demand for a fee. This was distributed through PBS's National Datacast. ====TV Guide On Screen==== TV Guide On Screen is an advertising-supported datacast sent by one local station in each media market. It supplements or replaces the limited electronic program guide sent by each TV station, which is already mandated by the U.S. Federal Communications Commission (FCC). ====ATSC-M/H==== ATSC-M/H is yet another mobile TV standard, although it is transmitted and controlled by the broadcasters instead of a third party, and is therefore mostly free-to-air (although it can also be subscription-based). From a technical standpoint, it is an IP-encapsulated datacast of MPEG-4 streaming video, alongside the ATSC MPEG transport stream used for terrestrial television broadcasting. Heavy error correction, separate from that native to ATSC, compensates for ATSC's poor mobile (and often fixed) reception. ====Qterics==== Qterics (formerly Broadcast Data Corporation and later UpdateLogic Incorporated's UpdateTV) is a service used by some brands of TV sets and other ATSC tuners to update their firmware via over-the-air programming. This is also transmitted on PBS stations via National Datacast. ===Australia=== Australian broadcast infrastructure company Broadcast Australia undertook a three-year trial in Sydney of a datacasting service using the DVB-T system for use in Australia. The trial consisted of a number of services on one standard 7 MHz multiplex, collectively known as Digital Forty Four. The collection included: A combined program guide for the free-to-air broadcasters (Channel 4) ABC news, sport, and weather items (Channel 41) Channel NSW (link) Government and Public Information, including real time traffic information and life surf webcam images (Channel 45) Australian Christian Channel (Channel 46) Expo Home Shopping (Channel 49) and Federal parliamentary audio broadcasts. More recently a near-Australia wide broadcast of a datacasting channel called MyTalk commenced on April 13, 2007. Broadcasting as part of the multiplex on Southern Cross and Southern Cross Ten stations, it provided news, weather and other information, available free to anyone able to tune in. The stream consisted of text applicable to the viewer's location and a 4:3 video window of terrestrial TV from the relevant Southern Cross/Southern Cross Ten station. On February 25, 2008, MyTalk ceased broadcasting. Digital Forty Four was shut down at exactly midnight on the night of April 30, 2010. ====Blockstream Satellite==== Blockstream Satellite broadcasts the Bitcoin blockchain via a global network of broadcast satellites. It also gives everyone the ability to transmit arbitrary files at low cost which can be received in total anonymity worldwide by anyone with a standard DVB-S2 receiver card or USB adapter. ====Outernet==== Outernet's goal is to provide free access to content from the web through geostationary and Low Earth orbit satellites, made available effectively to all parts of the world. The project uses datacasting and User Datagram Protocol (UDP) through both small satellites, such as CubeSats, and larger, more conventional geostationary communications satellites in a satellite constellation network. Wi-Fi enabled devices would communicate with the satellite hotspots, which receive data broadcasts from satellites.

Text derived from https://en.wikipedia.org/w/index.php?oldid=1317480466 under CC BY-SA 4.0; modifications have been made.