"Region coding" generally refers to the practice of limiting the use or playing of certain electronic media to specific geographic areas. Deliberate region coding started on [=DVDs=], and it mostly applies to films and video games.

Studios do this to control the global release and distribution of their works. They justify it by claiming that it takes time to produce translations for foreign languages, clear [[CensorshipBureau censorship standards]], abide by copyright terms, and pay local distributors around the world. People generally see this as a weak justification in an age of instant digital distribution, and they point out that this occurs even in places like the UK and Ireland which have no translation requirements and such for a film or game made in the United States.

In most countries, including the United States, it's considered illegal and a form of circumventing CopyProtection to disable region coding. However, in some countries, region coding ''itself'' is illegal as violating free trade agreements; Hong Kong, Australia, and New Zealand all require DVD players sold there to be region-free.

The practice has it's roots in VHS and Betamax; though an analog format, footage was purposely recorded at different speeds in NTSC and PAL regions making them incompatible with UsefulNotes/{{VCR}}s of other regions, unless you could find a special region-free VCR.

[[foldercontrol]]

[[folder:[=DVDs=] and Blu-rays]]
DVD players were the first to use widespread and specific region coding. DVD players assign a number to each region; a DVD with one region number cannot be played on a DVD player with a different region number. The same system applies to UsefulNotes/PlayStationPortable [=UMDs=] and software. The specific region codes are:
* '''0:''' Either no set region or regions 1-6; this applies to a DVD that can be played on any DVD player anywhere in the world or a DVD player that can play [=DVDs=] from any region.
* '''1:''' The US, Canada, and Bermuda.
* '''2:''' Most of Europe and the Middle East, South Africa, Swaziland, Lesotho, and Japan.
* '''3:''' East and Southeast Asia except for China, Japan, and North Korea.
* '''4:''' Australia, New Zealand, Papua New Guinea, and Latin America (except French Guiana).
* '''5:''' Africa (except Egypt, South Africa, Lesotho, and Swaziland), South Asia (including India), Central Asia, Russia, Ukraine, Belarus, Mongolia, and North Korea.
* '''6:''' Mainland China.
* '''7:''' Reserved for internal use by the MPAA; often used for copies sent to censors and critics before consumer release.
* '''8:''' Distant transportation venues, such as airplanes and cruise ships, for use in international skies and waters, although many of these venues just use the format and player type of their home nations.
* '''9:''' All eight regions combined.

Region coding was predictably one of the first things to be cracked on DVD players. In the United States, it's technically illegal to circumvent region coding, as with any UsefulNotes/{{DRM}}. In other countries, it's completely legal, but it may invalidate your warranty on some devices. A few countries, like Australia, New Zealand, and Hong Kong, have made DVD region locking illegal and require all DVD players sold there to be region-free or have the ability to turn off region coding. In other countries, like Sweden, Malaysia and the Philippines, you can easily get a region-free DVD player, but you have to ask for a region-free one specifically, otherwise you're getting the region-locked one by default.

UsefulNotes/BluRay discs have their own region coding, which are much less torturous:
* '''A:''' The Americas and most of Asia;
* '''B:''' Europe, Africa, Australia, and New Zealand;
* '''C:''' China, the former USSR, and other parts of Asia not covered by Region A.
[[/folder]]

[[folder:Video Game Consoles]]
Most older video game consoles have a natural region coding simply because of different television display formats on analog sets. Even in the digital age, this is likely to continue thanks to sheer tradition. Most of the world is split between PAL (Europe, Oceania and Asia) and NTSC (the Americas and some Asian countries), with further splits in NTSC formatting for video games between the Americas, Japan, China, and Korea. However, additional region locking devices have been around since the 1980s, ostensibly to prevent piracy but which effectively acted as a region coding scheme. Devices that circumvent this protection are technically illegal but remain popular for certain systems to facilitate ImportGaming.
* Nintendo was the first to introduce region locking on the UsefulNotes/NintendoEntertainmentSystem in 1984 with a lockout chip called the [=10NES=]. While its purpose was to prevent piracy and UsefulNotes/{{Shovelware}} by ensuring that only Nintendo-certified games would run on the system, it had the side effect of region locking the console; the US and European versions all had slightly different versions of the chip, so a game that ran on one version would not run on the others, while the Japanese version lacks the 10NES chip completely. Also notable was the original Japanese Famicom had a cartridge slot with fewer pins than the export NES, and it also had a [=DB15=] expansion port which was removed from the US version, preventing US gamers from using Japanese peripherals and cartridges. However, an adapter can be found in many older NES cartridges, salvaging one is considered a worthy sacrifice of the cartridge as the adapter has the 10NES matching chip onboard, meaning any game plugged in to the adapter will work on the target NES.
* The [[UsefulNotes/SuperNintendoEntertainmentSystem Super NES]] had the same copy protection chip on all consoles worldwide, so preventing shovelware didn't imply region locking on that system; but the SNES did have two plastic tabs that physically prevented you from inserting a Japanese Super Famicom game into the system (a scheme later used by the UsefulNotes/Nintendo64). You could fix that with a pair of pliers (and a willingness to void your warranty), but you would still run into problems trying to play a PAL game on an NTSC console or vice-versa as many games would detect an incorrect speed and display a message telling you that your game is in the wrong region, made possible in that PAL SNES systems ran at a slower speed compared to their NTSC counterpart. One common way to work around this is with a cheat cartridge like the Game Genie or Pro Action Replay, which can work as a passthrough by allowing one to piggyback the wrong region cart on top of the cheat cartridge (which can then also be conveniently used to disable the console speed check on the game), or less commonly, a region adapter, which is essentially a cartridge with ''two'' cartridge slots on it. Both ways have limitations in that games that have their own co-processor still won't work, and some games that rely tightly on the console's timing (ie the opening music of Tales of Phantasia) will glitch.
* The UsefulNotes/SegaGenesis has an odd region coding system. Sega, trying to cut costs, designed the console so that changing the region is as simple as swapping a few jumpers on the motherboard to change the console's clock speed and language. Once you did that, you could effectively change the console's region (although you did have to fiddle with Japanese cartridges to get them to fit into other regions' consoles and vice-versa). Chinese companies also made several "region adapters" that plugged in between the console and the cartridge. Early games never even bothered with region coding; some even used the settings for CountrySwitch purposes.
* Early portable consoles tended to lack region coding, on the theory that ''(a)'' they don't use a TV and ''(b)'' since you can easily take the system anywhere around the world, you should be able to play any game you may find there. But later portable consoles made extensive use of region coding:
** The Nintendo UsefulNotes/DSi has region locking, but only for specific [=DSi=] features, such as online compatibility; only downloadable games have region coding themselves.
** The UsefulNotes/Nintendo3DS has region locking for both cartridge and downloadable games. Nintendo allegedly incorporates a whitelist database on each device, which contains a list of valid games; games not on the list won't run. This is supposedly why the [=3DS=] regularly gets updates even when there are no new features or bug fixes, and why original DS cartridges need to be validated online (resulting in you needing Internet to play a DS game on a 3DS) before they added a separate DS whitelist.
** The [[UsefulNotes/PlayStationPortable PSP]] has region coding for UMD movies, the same as for [=DVDs=], and it also has optional region coding for games; for instance, EA used it to lock copies of ''VideoGame/{{BattleZone|2006}}'' sold in Asia so that they would only play on Asian [=PSPs=] (probably because it's so much cheaper in Asia than elsewhere). Sony also uses region coding to limit certain features and applications; Asian [=PSPs=] will not detect or launch the comic book viewer app, and only Japanese and British [=PSPs=] can use the Remote TV Viewer app to remotely watch content received and recorded by the [=PS3=] USB tuner (which was only sold in the UK and Japan).
* Strangely, only two UsefulNotes/PlayStation3 games have any region locking. One is ''VideoGame/Persona4Arena'', which caused Atlus a lot of flak due to the game's [[http://www.eurogamer.net/articles/2012-08-22-persona-4-arena-delayed-in-europe extremely delayed European release]] (although it was totally region-locked elsewhere, even between regions which already had the game. Atlus claims that the region-locking was to dissuade Japanese and European players from importing the cheaper US version. This not only angered certain Europeans[[note]]specifically, English speaking ones from the UK[[/note]] who already see themselves as being the victim of unfair price hikes, but things got worse when the European version was severely delayed with the existing launch date withdrawn and a new launch date not announced until early 2013); there was such a backlash to that decision (leading to European gamers cancelling pre-orders and threatening to boycott the launch) that Atlus didn't dare do it again[[note]]It also ended with Atlus being acquired by a revived Sega[[/note]]. The second is ''VideoGame/JoySoundDive'', a Japanese PSN exclusive game, which not only won't run on a non-Japanese [=PS3=], it won't even run on a Japanese [=PS3=] which recognizes that it's not in Japan; this is likely because it's a [[KaraokeBox karaoke game]] and JASRAC (the Japanese RIAA counterpart) would complain otherwise about music reproduction rights. Some other games (like ''[[VideoGame/GundamVsSeries Mobile Suit Gundam Extreme vs. Full Boost]]'' and ''VideoGame/ArmyOfTwo'') are region-free but have region-locked online play, ostensibly to prevent extreme imbalances in ability between regions.
* UsefulNotes/TheEighthGenerationOfConsoleVideoGames may be heralding the end of region locking in home video game consoles. Sony received such a backlash from its two region-locked [=PS3=] games that it pledged a region-free UsefulNotes/PlayStation4. Microsoft originally intended to region-lock the UsefulNotes/XboxOne to only 21 countries, but backed out when critics vocally protested. Nintendo, ever concerned about UsefulNotes/{{shovelware}}, maintained region coding on the UsefulNotes/WiiU, but it abandoned it for the UsefulNotes/NintendoSwitch, making it the company's first ever region-free home console. Although region locking remains an option for developers, few of them want to deal with that anymore.
[[/folder]]

[[folder:Encoding Standards]]
We've mentioned this before, but one way to enforce region locking (whether you want to or not) is through encoding standards -- that is, the way a television picks up signals and sends them to your screen. This would affect VHS, DVD, video games -- anything that uses a TV. If your film or game uses a different encoding standard than the TV you're trying to watch or play it on, it won't work.

The analog TV standards are PAL, SECAM, and NTSC. In general, NTSC was used in the Americas (except Brazil, Argentina, Uruguay, and Paraguay), Japan, Korea, Taiwan, Burma, and the Philippines; SECAM was used in France, the former Soviet Union, West Africa, and other French possessions (current and former), and PAL was used for most of Europe, most of Asia, the rest of Africa and South America, Australia, and New Zealand. The main difference arises in the color encoding standards and the "refresh rate" (''i.e.'' how the TV knows when and where to put the frames on the screen).

Then there's the transmission standard, which is further divided into System A through System S, which determines the image and sound modulation as well as the refresh rate: A TV meant for China, which uses PAL-D, will produce static noise despite having a clear picture, when receiving PAL-B signal, which is used in Australia, due to technical differences regarding audio defined by the transmission system. In some cases images are even inverted, and may be rolling due to different refresh rates used by different transmission systems. Additionally it's possible to mix and match transmission and color encoding standards, as seen egregiously in Brazil where the PAL color standard is used on top of System M, the basic black and white signal normally used for ''NTSC'' broadcasts, ensuring that PAL [=TVs=] from outside the country can't be used at all while NTSC [=TVs=] from North America can only pick up a black and white signal.

And then there are the frequency ranges, divided into CCIR which is typically used in most of the European Union as well as countries that are part of the British Commonwealth except Australia, OIRT which typically used in countries who deployed the SECAM color system (although China uses it with PAL color, albeit with the System-D and System-K transmission standard), and NTSC which is used in the US (NTSC can mean both the color system and the frequency boundaries defining VHF and UHF in the Americas region). However Japan and Australia have their own ranges that defer from other NTSC and PAL countries. France also previously used their own range while broadcasting in System E, but had since abandoned it for OIRT. Believe it or not, different parts of the world have different ideas on what frequency range constitutes as VHF and UHF. Historically, the biggest barrier from using a Japanese TV in the US is that the Channel 5 used in Japan (176MHz) is actually four megahertz off Channel 7 (180MHz) in the US, ensuring that it will never be able to get a clear picture unless the TV is readjusted by a qualified technician. In fact, this is the main reason it is so difficult to hook up a [[UsefulNotes/NintendoEntertainmentSystem Famicom]] to a North American TV in that the TV has to have a built-in cable tuner to be compatible with a Famicom: the Famicom's RF output puts out the signal at a frequency that is within Japanese VHF specs, but out of spec of the NTSC VHF band range and in the range of the NTSC CATV band instead.

It wasn't as bad as you'd think, though. Because PAL and SECAM use the same frame rate standards, it's possible for one system to show another tape, but only in black and white because of the different color standards- most of the time: most PAL [=VCRs=] would be hard-pressed to play Brazilian tapes as the country used the PAL color standard on top of ''System M'', the baseline transmission standard typically used for ''NTSC'' elsewhere. Conversely, NTSC [=VCRs=] in North America has the strange quirk of being able to play back PAL tapes in black and white, but only those from Brazil, as Brazilian [=VCRs=] ran at NTSC speed despite storing color in PAL. Some later VHS machines in the UK could even adjust to play US-format NTSC tapes. And Asia had a ton of world-multi [=VCRs=] and TV sets just because of the different standards used all over the place (largely based on which Western power ran the place when the system was implemented, and also the country's trading partners at the given time).

Video game consoles had a region locking scheme based on this with standards like PAL (Europe, Australia and New Zealand as well as South Africa) NTSC-U/C (the Americas), NTSC-J (Japan and much of Asia), NTSC-K (Korea), and NTSC-C (China), which don't even have anything to do with the transmission standards we just described. For the most part, though, they didn't differ too much in how a game was displayed on the screen.

In the digital age, we don't need analog standards anymore, but this just leads to different classifications. There are four digital systems now: ISDB is used in most of Latin and South America, Japan, the Philippines, Sri Lanka, and Botswana in Africa; ATSC is used in North America and it's foreign territories, and South Korea; DVB is used in Europe, most of Africa, the rest of Asia, and several outlying South American countries; and DMB is used in China (and as a secondary system for portable receivers in South Korea, which technically uses a different version incompatible with the Chinese version). To further complicate matters, there are two versions of DVB, and tuners built for version 2 are backwards-compatible with version 1, but not vice-versa, which causes headaches for early adopters in countries like Malaysia and Singapore as the country started with version 1 of the DVB standard but migrated to version 2 eventually. And yes, the multiple variants of ISDB implemented in South America and the Philippines are said to be not compatible with each other, let alone it's original Japanese variant,[[note]]Although there are reports that some JP TV tuners (Like the Portable TV tuner add-on for the PSP and Brazilian released Smartphones with [=1Seg=] tuners) imported to the Philippines for ISDB signal tests conducted during the test broadcasts of some channels with ISDB digital signals are compatible with the Philippine version of ISDB.[[/note]] although it is later revealed that The Philippines, Japan and South America has entered an agreement which standardized the version of ISDB used in the countries- the new version of ISDB deployed by Botswana, Sri Lanka, The Philippines and South America is called ISDB-Tb and only differs from the original Japanese version by means of ''reception frequency'' (Japan's VHF/UHF frequency range traditionally is unique to Japan itself). It's incredibly difficult for a country to change standards, too (just ask Thailand, who dumped NTSC for PAL in 1989). And to top it off, HD images can be 24, 25, or 30 frames per second, and many American [=TVs=] refuse to recognize 25fps input.
[[/folder]]

[[folder:Cell Phones]]
Cell phones are weird, as they tended to be region locked based on frequency range (before modern cell-phones went to multi-band world phones, and even then many lower end modern phones and even some high end ones only supported the bands in the region the phone is sold in). A cell phone in one region wouldn't be compatible with the cell network in another. This is in addition to SIM-locking, where the phone can only work with a SIM card from the company that sold you the service (a practice which isn't even legal in all countries).
* In the 2G era, it was usually the American [=850MHz/1.9GHz=] against the rest of the world's [=900MHz/1.8GHz=]. Tri-band 2G phones would work with all telcos in their home region and select telcos in other regions, and Quad-band 2G phones would allow you to use networks in both regions.
* In the 3G era, it got more complicated. The US used [=850MHz/1.7GHz/1.9GHz=], most of the rest of the world used [=900MHz/2.1GHZ=], and Japan, Korea, and Australia had their own [=800MHz=] band (but only for very isolated places like the Australian outback). Penta-band 3G phones would work everywhere except those isolated places, and hex-band 3G phones would work everywhere.
* In the 4G era, we've now got at least nine bands: the US uses [=700MHz/1.7GHz/1.9GHz=], most of the rest of the world uses [=800MHz/1.8GHz/2.6GHz=], and some third-world countries use [=850MHz/900MHz/2.1GHz=][[note]]and that's just oversimplification as each of these bands also have variants in return channel frequencies as well as the actual band range, the [=700MHz=] range actually has ''five'' variants[[/note]]. Then you have the TDD frequencies - 2.3, 2.5, and 3.5 [=GHz=]. So far, there is no world-capable phone that can support all of the bands, but several phones can support all the non-TDD ones.
* Samsung region-locks their phones so that they may only be used in the country they're sold in, even if the phone itself isn't SIM-locked. This means that a Galaxy S5 that you buy in, say, Malaysia, can't use a Singaporean SIM card in Singapore even if you could freely swap between SIM cards of any provider in Malaysia.
[[/folder]]

[[folder:Power Supply]]
The most primitive form of region coding, where the power is divided between "old world" (220v-240v) and "new world" (100v-120v). This is further divided into 50Hz/60Hz alternations, with Japan using both 50Hz and 60Hz alternations- with 50Hz covering the West and 60Hz covering the East- even though voltage is normalized at 100v. For the rest of the world it's far more straightforward- the "old world" (most of Asia, Europe, Africa and Oceania) uses power that is normalized at 230v and alternates at 50Hz, while the "new world" (read: The Americas, as well as areas in Asia previously occupied by US forces) uses power that is normalized at 110v and alternates at 60Hz. Unless a device has been rated for all four voltages and both alternation frequency, it's bad news to plug a device not intended for the voltage into the outlet without a conversion transformer, especially with regards to "new world" devices in "old world" regions, where the outcome would be a loud pop and smoke, and fire if you're really unlucky.

For many devices with a wall wart or power brick, the solution would be to source a wall wart meant for the region's equivalent of the device and using that with the old device. However for devices that uses AC power directly, a conversion transformer is often needed. Some devices like desktop computer power supplies and boomboxes may have a voltage selector switch hidden somewhere, usually in a discreet location around the back or inside the device.

This is usually mitigated on charger wall warts meant for portable devices like laptops, cellphones and camcorders, as it is understood that these devices are to be used anywhere in the world and thus need to be able to charge off any wall socket available regardless of the country's power specifications.
[[/folder]]

[[folder:The Greater Internet]]
The Internet is becoming the new region coding battleground. Companies will release content on the Internet but restrict viewing or accessing it to certain regions, as verified by IP address. Some services, like Website/YouTube, even allow people to upload their own videos and region-lock them.
* Online content providers occasionally lock by region:
** Creator/TheBBC [=iPlayer=] is one of the earliest and most prominent examples. This is because the BBC is funded by a license paid by every household in the UK to allow them to legally watch broadcast television, which makes it otherwise free in the UK. Outside the UK, you can't watch the streaming service because you haven't paid for it. But within the UK, you don't have to pay the license if you don't actually ''have'' a TV, but you can still watch the [=iPlayer=] since there's no way for the BBC to verify that you do pay the license, making this a very attractive option for cord-cutters; the BBC is having such trouble with this that there's talk of dropping the [=iPlayer=] restriction entirely. That said, there have been awkward instances where the BBC in the UK uploads something, only for BBC Worldwide, the international profit-making arm, to block it for copyright reasons.
*** BBC Worldwide has recently launched a version of [=iPlayer=] now christened ''BBC Player'' in Asia. the catch? It's only available to subscribers of a particular cable company in Singapore and Malaysia respectively. Those outside the two countries, or even those in the two countries but are subscribed to a different ISP, are blocked off access to the service.
** Creator/TheABC in Australia has its [=iView=] system similarly blocked to non-Australians, but the ABC offers its programming for free just on principle; there is no TV license in Australia like there is in the UK. The ABC claims it's due to licensing issues -- ''i.e.'' it costs too much for them to ensure that they have the rights to show something outside of Australia -- but they do this even to shows they've produced themselves, which is particularly mind-boggling. It turns out that they have changed their tone and no longer want to offer their programming to those living outside Australia for free- those living outside of Australia would need to get a ''paid channel'' called Australia Plus TV from their local pay TV provider to get ABC shows, tough luck if their provider doesn't carry that channel. Additionally, they've started engaging in {{International Coproduction}}s to save on cost, and part of the side effect of that is that it muddies production ownership enough that they cannot offer shows for free if the partner company chooses to sell the shows instead.
** And then of course there's Creator/{{Hulu}}, the bane of forum and blog readers stationed outside the US and Japan. Unlike Netflix and Amazon Prime Video, Hulu has made no effort to expand worldwide, only empty promises (the expansion to Japan was only possible due to a partnership with Nippon TV- meaning Nippon TV had to ''invite'' Hulu into the market, and did the brunt of the work setting up the system for Hulu).
** While Creator/{{Netflix}} is now available worldwide, it still has region coding; not every show is available in every region. It often happens in a show's home country, where it may be licensed exclusively to some other provider, but which can be shown outside that country on Netflix. This tends not to happen with Netflix exclusives, but you still see it (such as the Netflix-exclusive seasons of ''Series/ArrestedDevelopment'' being unavailable in Asia).
** [[Creator/AmazonStudios Amazon Prime Video]] is available in more than 200 countries, of which all but six only have access to a little over a hundred titles; the six (US, UK, Germany, Austria, Japan and India) are the first to get pretty much everything. This is because they are the primary targets for the service currently; all other countries are served by a different website and are effectively a seperate (inferior) service, apparently a placeholder while Amazon is behind and playing catch-up to Netflix in global expansion.
* This happens in online video games too:
** Many {{MMORPG}}s have a variant of region coding which prevents you from playing the game if it detects that you are connected to the Internet outside its region. Sometimes this is to ensure that players are matched up with similar players. Other times, it's to ensure compliance with local laws; in Korea, for instance, MMO hosts are required to verify the identities of every registered user, and they usually do this by asking for a Korean resident registration number and copy of a Korean ID card which foreigners wouldn't be able to supply.
** Creator/{{Konami}}'s [=eAMUSEMENT=] Participation program, used for some Konami arcade games, requires a connection to the [=eAMUSEMENT=] network in order for the game to work. These services are limited to Japan, some other Asian countries, and the United States (thanks to the presence of Japanese-owned arcade chain Round 1); these arcade games cannot be played in any other country. Unfortunately for Konami, this led to the proliferation of {{Shoddy Knockoff Product}}s in these parts of the world, and parallel importers also found out that Konami ''did'' make versions of these games that did not need [=eAMUSEMENT=] to function for the Chinese market.
** Buying ''VideoGame/TeamFortress2'' from a German IP address will result in it being permanently locked in "party mode", which replaces the LudicrousGibs with objects like cake slices and candy.
* Online stores often do some form of region locking, often by only accepting credit cards from within their own countries. It's particularly annoying when they will still happily let you search and browse through the entire catalog, only for it to tell you you're not allowed to buy what you've found in your region.
** Amazon locks its [=MP3=] store by preventing you from buying anything unless your IP address belongs to an ISP in the country the store is in. Its app store was also initially only available to a few countries; in earlier years, this mapped to countries where the Kindle was sold.
** Apple's app store is rather irrationally segregated by region. Certain apps might not be available in your country, even if other apps by the same developer are. It's weird enough for there to be a form to request Apple to make the app available (but it's final availability is at the developer's discretion). Apple prefers to do its copy protection through UsefulNotes/{{DRM}} anyway.
** Most AndroidGames are not region locked, but some can't be downloaded from the Play Store in certain regions. There are workarounds, though, you could easily move your game to your other phone since the APK files aren't encrypted, except you can't update it to a new version, and certain games are coming up with their own third party DRM anyway- using APK extension, which can be region locked through several means (including GPS location, your telco's MNC code, and basic IP georestrictions).
* Franchise/LeapFrog's latest endeavour, Leapfrog Academy, is currently only effectively available in the US, UK, Canada, Australia and New Zealand. If you live outside those 5 countries, you can't sign up for the service, their system is designed to reject credit cards that are not from the 5 mentioned countries.
[[/folder]]
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