A SIM lock, simlock, network lock or subsidy lock — not to be confused with PIN or PUK code — is a capability built-in to GSM phones by mobile phone manufacturers. Network providers use this capability to restrict the use of these phones to specific countries and network providers. Currently, phones can be locked to accept only SIM cards from one or more of the following: PINs are most often used for ATMs but are increasingly used at the Point of sale, especially for debit cards. ... This article or section does not cite its references or sources. ... For other uses, see GSM (disambiguation). ... It has been suggested that Virtual sim be merged into this article or section. ...

• Countries (the phone will work in one country, but not another)
• Network/Service providers (e.g. AT&T Mobility, T-Mobile, Vodafone, etc.)
• SIM types (i.e. only specific SIM cards can be used with the phone).

In some countries, most mobile phones are shipped with country and/or network provider locks. In addition, these locked phones tend to have firmware installed on them which is specific to the network provider. For example, if you have a Vodafone or Telstra branded phone in Australia, it displays the relevant logo and may only support features provided by that network (i.e. Vodafone Live!). This firmware is installed by the service provider and is separate from the locking mechanism. You can unlock most mobile phones to work with any GSM, such as O2 or Orange (in the UK) but the phone may still display the original branding and may not support features of your new carrier. Most phones can be unbranded by uploading a different firmware version, a procedure recommended for advanced users only. This article is about the wireless subsidiary of AT&T. For the defunct wireless provider that was merged into Cingular in 2004, see AT&T Wireless Services. ... T-Mobile logo T-Mobile is a multinational mobile phone operator. ... Vodafone Group Plc is a mobile network operator headquartered in Newbury, Berkshire, England, UK. It is the largest mobile telecommunications network company in the world by turnover and has a market value of about £84. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ... For other uses, see GSM (disambiguation). ...

Types of SIM locks

The country lock only allows the use of the phone with SIM cards that originated in a specific country or group of countries.

A network lock only allows the use of the phone with SIM cards that belong to a specific network.

The most common lock is the service provider lock (SP-lock). Many different service providers may use the same physical network (e.g. MVNOs). An SP-lock ensures that the handset is only used with SIM cards for the same service provider that marketed the handset. Service providers sometimes substantially subsidize handsets, and locking the handset improves the odds that its use will economically benefit the service provider. A Mobile Virtual Network Operator is a company that does not own a licensed frequency spectrum, but resells wireless services under their own brand name, using the network of another mobile phone operator. ...

The most restrictive type of lock which can be used is the full SIM card lock, which means that a phone will only work with one SIM card. If that SIM card malfunctions or is damaged, the phone will no longer work and must be serviced.

Some carriers may have separate locks for the different countries they operate in, so that a phone purchased in America may not work with a carrier's British counterpart or vice-versa.

Laws On SIM/Network Locking

This section does not cite any references or sources. (June 2008) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

In many countries, locking a handset is legal and may even be required. Some providers never unlock handsets, even after a customer has fulfilled their service contract.^{[citation needed]}

On the other hand, SIM locking has countercompetitive effects on the cellphone service market. In some countries, this is considered sufficiently undesirable to warrant regulation or prohibition of the practice.

Belgium is the only European country that outright forbids simlocking and contract/phone bundling. Currently there are 2 cases in front of the European Court of Justice that will determine whether Belgium's laws are forbidden under 2005 EC directives. Belgium government ministries have been studying this for the last couple of years and are currently undergoing steps to repeal the laws in question.

In the United States, one of the two national GSM carriers, T-Mobile [1], will unlock your handset if you have an active account in good standing for at least 90 days. The other, AT&T Wireless [2], will sometimes not do so until you have concluded your contract, but may unlock the phone in some situations. The US does NOT have any simlocking regulations --- and American GSM carriers are still providing unlocking codes for free. T-Mobile logo T-Mobile is a multinational mobile phone operator. ... AT&T Wireless Services, Inc. ...

In the United Kingdom, cellphone network providers don't have to provide unlocking codes at all even after the end of the contract --- see O2's position of not providing unlocking codes for the iPhone at the end of the contract.

In France, the simlocking laws were bypassed by Apple by offering an unlocked iPhone at a much greater price.

In Germany, T-Mobile only "promised" to provide unlocking codes for the iPhone --- only after they were being sued by Vodafone in the injunction case. Notice that Vodafone's injunction was later overturned --- thus meaning that there are no effective simlocking laws in Germany.

In The Netherlands and Spain, providers must provide unlocking codes, but can charge a fee for this during the first 12 months after purchase.

In Hong Kong, carriers are not allowed to SIM lock a phone for the purpose of SOLELY tying customers to their network. But Hong Kong carriers can SIM-lock a phone to protect the handset subsidy or to enforce mobile plan contracts or to protect from theft.^[1]

In Finland carriers are not allowed to sell simlocked GSM phones, but they can simlock 3G handsets.

In Australia, carriers can choose whether to SIM/Network Lock handsets or not and usually tend to only SIM/Network lock prepaid handsets --- thus there is no regulation or law on simlocking in Australia.

In Canada, the country's only GSM carrier is Rogers/Fido, and they will not provide official support for unlocking their products.

Unlocking technology

A handset can be unlocked by entering a special code, or in some cases, over-the-air by the carrier.

Typically, a locked phone will display a message if a restricted SIM is used, requesting the unlock code.

For example, on the Sony Ericsson T610 mobile phone, "Insert correct SIM card" will appear on the phone's display if the wrong SIM is used. Once a valid unlocking code is entered, the phone will display "Network unlocked". In some cases, the phone will simply display a message explaining that it is locked. This is especially the case with handsets provided by AT&T Mobility. For an arrangement of Sony Ericsson products, see list of Sony Ericsson products Sony Ericsson is a joint venture established in 2001 by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to make mobile phones. ...

The code required to remove all SIM locks from a phone is called the master code or network code key.

The unlock code is verified by the phone itself, and is either stored in a database or calculated using an obscure mathematical formula by the provider. In cryptography and computer security, security through obscurity (sometimes security by obscurity) is to some a controversial principle in security engineering, which attempts to use secrecy (of design, implementation, etc. ... For other meanings of mathematics or uses of math and maths, see Mathematics (disambiguation) and Math (disambiguation). ...

The algorithms used in earlier Nokia brand phones (based on IMEI and MCC code) have been reverse engineered, stolen or leaked, resulting in many people offering Nokia unlock codes for free or for a fee. Newer Nokia phones have more robust encoding algorithms and permit fewer attempts at unlocking and are not unlockable by these free unlocking programs. This article is about the telecommunications corporation. ... The International Mobile Equipment Identity (or IMEI) is a unique number associated with every GSM and UMTS mobile phone. ... This is a list of Mobile Country Codes (MCCs) defined in ITU E.212 (Land Mobile Numbering Plan) for use in identifying mobile stations in wireless telephone networks, particularly GSM. The MCC is part of the International Mobile Subscriber Identity (IMSI) number, which uniquely identifies a particular subscriber, and is...

Many other manufacturers have taken a more cautious approach, and embed a random number in the handset's firmware that is only retained by the network on whose behalf the lock was applied. Such phones can often still be unlocked, but need to be connected to special test equipment that will rewrite that part of its firmware where the lock status is kept. Random redirects here. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ...

Most phones have security measures built in its software that prevent users from entering the unlock code too many times, usually four. After that the phone becomes "hard-locked" and special unlocking equipment has to be used in order to unlock it.

Handset manufacturers have economic incentives both to strengthen simlock security (which placates network providers and enables exclusivity deals), but also to weaken it (broadening a handset's appeal to customers who are not interested in the service provider that offers it). Also, making it too difficult to unlock a handset makes it less appealing to network service providers that have a legal obligation to provide unlock codes for every handset they've ever sold.

The main reason to unlock a phone is to be able to use it with a different SIM card. For example, when traveling abroad it's usually cheaper to temporarily use a foreign network, for example with a prepaid subscription. Contrary to some beliefs, an unlocked phone can't access extra cell phone towers or give free phone service. All it can do is accept other SIMs. Prepaid telephone calls are a popular way of making telephone calls which allow the caller to control spend and not be tied into ongoing commitments with the telephone operator. ...

In some cases, a simlocked handset is sold at a substantially lower price than an unlocked one, because the service provider expects income through its service. A consumer may choose to unlock the phone and continue using his previous provider. Therefore, simlocks are usually employed on cheaper (pay-as-you-go) handsets, while discounts on more expensive handsets require a subscription that provides guaranteed cash flow. Pay As You Go, often shortened to PAYG, is the general term for the concept of a prepay mobile phone. ...

A practice known as "box breaking" is common in the UK and some other markets. This involves purchasing (usually) pay as you go handsets from retail stores, unlocking the phones, and then selling them (often abroad) for a higher price than the subsidised retail price. The SIM card that came with the subsidized handset is then either thrown away or sold or used elsewhere. This practice is entirely legal in the UK, and provides a de-facto limit to the extent to which networks are willing to subsidize pay as you go handsets. In recent times network operators have been insisting that new customers purchase substantial amounts of airtime at the same time as they buy a new handset, in order that the total price they pay comes close to the true value of the handset. Look up De facto in Wiktionary, the free dictionary. ...

Unlocking via code

Some companies have begun to offer an e-mail unlocking service. This service requires that the individual who wishes to unlock their phone emails his or hers IMEI number (you can find this by pressing *#06# on your phone) to the company. The company will then process this IMEI number and email back an unlock code and instructions. Input the unlock code and your phone is unlocked. These email services are usually the most efficient as it is the same method most retail stores will offer. The International Mobile Equipment Identity (or IMEI) is a unique number associated with every GSM and UMTS mobile phone. ...

Unlocking via mail

Some companies have begun to offer a "mail-in" service. These services allow the user to send their phone in and have it sent back in an unlocked condition. The benefit to this is that the user doesn't have to become a "cell-phone technician" and also comes with the assurance of a money back guarantee.^[2]

Spoofing SIM data

In 2004, a company BLADOX in the Czech Republic released a small device called a Turbo SIM which contained a small MCU capable of spoofing the network ID during SIM registration. This thin device sits between the SIM card and the phone, in the SIM slot. A small piece of plastic on the SIM is removed to make room for the MCU. The most popular of these devices, originally for the U.S Apple iPhone, is typically called "China3GPP" after a label printed on the card. It has been suggested that this article or section be merged with embedded microprocessor. ...

Regulations on unlocking

Unlocking a phone without the permission or unlocking code from the provider is usually in breach of the agreement with the provider, though most countries do not make specific laws prohibiting the removal of SIM locks. (In many markets, it is also unlikely that a customer would prematurely unlock a pay-as-you-go phone over the counter, since they are not legally bound by any such contract anyway).^{[citation needed]} For example, in Poland, the law states that providers cannot word their customer contracts so that they forbid the removal of SIM locks, and the process is entirely legal providing that the IMEI number of the phone is not changed during the unlocking process.^{[citation needed]} For other uses, see Law (disambiguation). ... This is a method of billing for a mobile phone. ... The International Mobile Equipment Identity (or IMEI) is a unique number associated with every GSM and UMTS mobile phone. ...

In the Netherlands unlocking is legal provided that the process does not overwrite the handset's flash memory with a (modified) copy of copyrighted firmware, since this would be a breach of copyright retained by the manufacturer. However, unlocking a handset may void its warranty. Not to be confused with copywriting. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ... In commercial and consumer transactions, a warranty is an obligation that an article or service sold is as factually stated or legally implied by the seller, and that often provides for a specific remedy such as repair or replacement in the event the article or service fails to meet the...

In the United States the DMCA formerly was claimed to criminalize unlocking. However, an exemption that took effect 27 November 2006 specifically permits it, and will expire in three years but it can be renewed after that.^[3] The exemption only applies to the actual unlocking, not to providing an unlocking device or service, see WIPO Copyright and Performances and Phonograms Treaties Implementation Act. The Digital Millennium Copyright Act (DMCA) is a controversial United States copyright law which criminalizes production and dissemination of technology that can circumvent measures taken to protect copyright, not merely infringement of copyright itself, and heightens the penalties for copyright infringement on the Internet. ... is the 331st day of the year (332nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... The WIPO Copyright and Performances and Phonograms Treaties Implementation Act, is a part of the Digital Millennium Copyright Act (DMCA), a 1998 U.S. law. ...

References

1. ^ OFTA, Office of the Telecommunications Authority, Hong Kong
2. ^ Rettie, John (2007-09-03). "Is it legal to unlock your Phone?", TUAW. Retrieved on 2007-10-16. 
3. ^ “Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control Technologies, Final Rule”, Federal Register 71 (227): 68472-68480, 2006-11-27, <http://www.copyright.gov/fedreg/2006/71fr68472.pdf>. Retrieved on July 3, 2007 .

Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 246th day of the year (247th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 289th day of the year (290th in leap years) in the Gregorian calendar. ... July 3 is the 184th day of the year (185th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ...

See also

• IMEI
• Mobile phone