EVT-BIF - (Enhanced Television-Binary Interchange Format) - A CableLabs specification for delivering basic interactive TV applications to older (current as of 2007) cable provider's set-top boxes as well as newer entry-level boxes that can't operate using cable's primary specification for interactive TV, Opencable Platform (formerly known as OCAP).  ETV-BIF is based on a simpler binary language, (Opencable Platform is based on Java.) After software is added to these less sophisticated set-top boxes, it can provide basic interactive TV applications.

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www.opencable.com/etv/etv_overview.html