SIM lock is prohibited in principle from October. What are the benefits and precautions on the user side?

Although it is a SIM required to communicate with smartphones, "SIM lock" that makes it impossible to use SIMs of other carriers will be prohibited in principle after October 1st.

However, smartphones sold in the future will be able to be used by inserting another company's SIM without having to unlock the SIM lock.

Because, after discussions at the "Switching Facilitation Task Force", a conference of experts held by the Ministry of Internal Affairs and Communications until May 2021, SIM lock impairs the convenience of terminal purchasers and hinders competition between carriers. This is because it was concluded that the SIM lock should be prohibited in principle.

On August 10, the Ministry of Internal Affairs and Communications announced a revised version of the "Guidelines for Ensuring Smooth Distribution and Use of Mobile Terminal Equipment" based on the results of the solicitation of opinions. According to this, SIM lock will be prohibited in principle from October 1, 2021. Then, what kind of change will occur in our smartphone usage if SIM lock is prohibited in principle?

In principle, the ban is scheduled for October 1, 2021, with the exception.

The biggest change is that smartphones released after October 2021 can no longer be SIM-locked in principle, and SIMs from other carriers can be inserted and used without the hassle of unlocking the SIM. That is.

For example, after purchasing a smartphone with au, it will be possible to insert and use SoftBank's SIM immediately, and it will be easier for consumers to switch to another carrier while using the same terminal, which is the biggest merit from the consumer's point of view. It can be said that.

Looking at the above guidelines, it seems that SIM locks are banned in principle over a wide range of smartphones, feature phones, tablets, mobile routers, and USB modems. Therefore, if the terminal was released after October 2021, you can basically think that you can switch to another company's line without worrying about SIM lock.

However, the prohibition of SIM lock is not "uniform" but "principle". For example, if the carrier determines that there is a risk of non-payment when the customer purchases the terminal in installments, check with the Ministry of Internal Affairs and Communications. It is allowed to lock the SIM lock.

However, even in that case, if the credit and payment can be confirmed, the carrier is required to unlock the SIM for free without the customer having to go through the procedure.

Not applicable to devices released before October

On the other hand, models released before October 1, 2021 are not subject to the revised guidelines. If you purchase such a device after October 1, 2021, it may be locked as before, and you need to be aware that you need to unlock it if you want to use another carrier's SIM. prize.

However, in fact, there are some carriers that already provide terminals with the SIM lock unlocked. Rakuten Mobile has not locked the terminals it sells from the beginning, and MVNOs have already taken similar measures. Also, from August 2020, NTT DoCoMo will hand over the device without SIM lock if the device is purchased in one lump sum or in installments by credit card.

On the other hand, KDDI and Softbank currently only respond to unlocking the SIM lock if the user requests it when purchasing in a lump sum or in installments by credit card, and it is thought that the same measures will be continued until the guideline is revised. ..

However, on August 10, SoftBank announced that it will automatically unlock the SIM if it transfers between SoftBank, Ymobile, and LINEMO brands. In addition, KDDI has said that it will sell the new model "Redmi Note 10 JE" made by Xiaomi under the au brand etc. without SIM lock in principle, in anticipation of measures to prohibit SIM lock in principle. There seems to be some changes in the response.

Precautions when switching to another company using the same terminal

It is certainly a benefit for consumers that SIM lock is prohibited in principle, but remember that it is not always the case if you can insert the SIM of another carrier into the same smartphone and use it comfortably. is needed. This is because the correspondence of frequency bands (bands), which are important for using mobile communication, differs depending on the terminal.

Actually, the bands assigned to the four mobile phone companies are not the same. For example, even if you compare the same band called the platinum band, there is a difference between NTT DoCoMo's 800MHz band (band 19) and KDDI's 800MHz band (band 18). There is, and the one assigned to SoftBank is the 900MHz band (band 8) and another band.

Moreover, terminals sold by major carriers are often designed so that each carrier can communicate comfortably using a band licensed by each carrier, except for some, which does not cover the major bands of other companies. There are many things unexpectedly. For that reason, if the band on the terminal side does not correspond to the band used by the contracted carrier, communication speed will be slow, communication will not be possible at a specific place, etc., and communication will not be comfortable. There is a possibility that it will end up.

For the compatible bands of each terminal, information is posted on the specifications table published by the manufacturer if it is a SIM-free terminal, and on the website of each carrier if it is a terminal sold by a carrier. When using a different carrier's SIM on a device that is not SIM-locked, it is essential to check the information in advance.

It is also important to know that if you are not familiar with smartphones and SIMs, you may not be able to communicate by simply replacing the SIM with another carrier. After replacing the SIM, you need to set the APN (Access Point Name, information necessary to connect to the Internet from the terminal), and if it is an iPhone, you will be asked to download the "configuration profile" to set the APN. May be.

In particular, when using the SIM of the MVNO or the SIM of the online-only plan such as "ahamo", you need to do all such settings and operations yourself, and the store does not support it. Just because the SIM lock is not applied does not mean that anyone can easily switch to another carrier, and it is important to know that switching requires a certain amount of knowledge about mobile communication.

Masahiro Sano

Born in Fukushima Prefecture, graduated from Tohoku Institute of Technology. After working on the development of digital content as an engineer, he turned into a writer specializing in mobile phones and mobile phones. He now writes in a wide range of fields related to mobile phones, from industry trends to culture.