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DVB-RCT
DVB-RCT (Digital Video Broadcasting - Return Channel Terrestrial), provides a method by which the DVB-T (and in theory DVB-T2 but DVB-T2 probably trialled first about 5 years after last DVB-RCT field trial) platform can become a bi-directional, asymmetric, data path using wireless between broadcasters and customers. DVB-T when completed with DVB-RCT can be used not only for Interactive TV (voting, quiz, etc.), but also for light IP telecommunication services. Various degrees of interactivity could be offered, without implying any return channel back from the user to the service provider: data carrousel or Electronic Programs Guides (EPG) are examples of such enhanced TV services which make use of “Local Interactivity”, without any return path from customer to provider.
To implement new interactive services having a closely coupled and real-time relationship with the TV programs (e.g., interactive advertising, tele-voting, tele-quiz), a low latency return channel technology is mandatory, and this is the goal of the DVB-RCT. Without adding a cellular style network with about x20 more masts no Internet usage except about 1/20th speed of analogue dialup would be feasible.
==Failure==
By 2006 the main developer of DVB-RCT Runcom had abandoned it (no deployments due to Mobile Phone Penetration) and switched the expertise to portable WiMax Modems and Infrastructure, later adding LTE. Many people mistakenly think DVB-RCT would have allowed Viewers to browse the Internet. Partially the mistaken Internet belief was due to the "It's TV" Proposal in Ireland in 2000/2001 and RTE-NL (now 2RN) 1999 field trials assisted by Runcom.
But peak time speeds using existing TV mast infrastructures would have provided about 1200bit/s or less. It could only have been used for in program voting or purchase of broadcast advert items (TV or Teletext, or later MHP / MHEG5 broadcast), very little per user download content. The Cable version DVB-RCC never succeeded in competing against Cablelabs DOCSIS though Internet by Satellite did use DVB-RCS, but Ka-Sat and others since 2005 are deploying Satellite versions of DOCSIS.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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