Editing ISDB (section)

==Introduction==
[[File:Digital broadcast standards.svg|thumb|500px|right|DTT broadcasting systems. Countries using ISDB are shown in green.]]

ISDB is maintained by the Japanese organization [[ARIB]]. The [[Integrated Services Digital Broadcasting#Standards|standards]] can be obtained for free at the Japanese organization [[DiBEG]] website and at ARIB.

The core standards of ISDB are [[Integrated Services Digital Broadcasting#ISDB-S|ISDB-S]] (satellite television), [[Integrated Services Digital Broadcasting#ISDB-T|ISDB-T]] (terrestrial), [[Integrated Services Digital Broadcasting#ISDB-C|ISDB-C]] (cable) and [[#2.6 GHz Mobile satellite digital audio/video broadcasting|2.6&nbsp;GHz band mobile broadcasting]] which are all based on [[MPEG-2]], [[MPEG-4]], or [[HEVC]] standard for multiplexing with transport stream structure and video and audio coding (MPEG-2, H.264, or HEVC) and are capable of [[Ultra-high-definition television|UHD]], high-definition television ([[High-definition television|HDTV]]) and standard-definition television. [[Integrated Services Digital Broadcasting#ISDB-T|ISDB-T]] and [[Integrated Services Digital Broadcasting#ISDB-Tsb|ISDB-Tsb]] are for mobile reception in TV bands. [[1seg]] is the name of an ISDB-T component that allows viewers to watch TV channels via [[cell phones]], [[laptop computers]], and [[vehicles]].

The concept was named for its similarity to [[Integrated Services Digital Network|ISDN]] as both allow multiple channels of data to be transmitted together (a process called multiplexing). This broadcast standard is also much like another [[digital radio]] system, [[Eureka 147]], which calls each group of stations on a transmitter an [[DAB ensemble|ensemble]]; this is very much like the multi-channel digital TV standard [[DVB-T]]. ISDB-T operates on unused TV channels, an approach that was taken by other countries for TV but never before for radio.

===Transmission===
The various flavors of ISDB differ mainly in the modulations used, due to the requirements of different frequency bands. The 12&nbsp;GHz band ISDB-S uses [[Phase-shift keying|PSK]] modulation, 2.6&nbsp;GHz band digital sound broadcasting uses [[Code division multiplexing|CDM]], and ISDB-T (in [[Very high frequency|VHF]] and/or [[Ultra high frequency|UHF]] band) uses [[Orthogonal frequency-division multiplexing|COFDM]] with [[Phase-shift keying|PSK]]/[[Quadrature amplitude modulation|QAM]].

===Interaction===
Besides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media ([[10/100]] Ethernet, telephone line modem, mobile phone, wireless LAN (IEEE 802.11), etc.) and with different protocols. This component is used, for example, for interactive interfaces like data broadcasting ([[ARIB STD-B24]]) and electronic program guides (EPG).

===Interfaces and Encryption===
The ISDB specification describes a lot of (network) interfaces, but most importantly, the Common Interface for Conditional Access System (CAS). While ISDB has examples of implementing various kinds of CAS systems, in Japan, a CAS system called "B-CAS" is used. ARIB STD-B25 defines the [[Common Scrambling Algorithm]] (CSA) system called [[MULTI2]] required for (de-)scrambling television.

The ISDB CAS system in Japan is operated by a company named ''[[B-CAS]]''; the CAS card is called ''B-CAS card''. The Japanese ISDB signal is always encrypted by the B-CAS system even if it is a free television program. That is why it is commonly called "Pay per view system without charge".{{Citation needed|date=September 2008}} An interface for mobile reception is under consideration.{{Citation needed|date=September 2008}}

ISDB supports RMP (Rights management and protection). Since all digital television (DTV) systems carry digital data content, a [[DVD]] or high-definition (HD) recorder could easily copy content losslessly.
[[Major film studios|US major film studios]] requested copy protection; this was the main reason for RMP being mandated. The content has three modes: "copy once", "copy free" and "copy never". In "copy once" mode, a program can be stored on a hard disk recorder, but cannot be further copied; only moved to another copy-protected media—and this move operation will mark the content "copy one generation", which is mandated to prevent further copying permanently. "Copy never" programs may only be [[Time shifting|timeshifted]] and cannot be permanently stored. In 2006,<ref name=":0" /> the Japanese government is evaluating using the [[Digital Transmission Content Protection]] (DTCP) "Encryption plus Non-Assertion" mechanism to allow making multiple copies of digital content between compliant devices.<ref name=":0">{{Cite web|url=https://japan.cnet.com/article/20094312/|title=JEITA、地デジのコンテンツ保護策として暗号方式 EPN を提案|date=January 12, 2006|website=CNET Japan}}</ref>