Smartphones that support DSDV (Dual Sim Dual Volte), which can use two SIMs at the same time, are increasing.The iPhone (XS/XR or later) is also such a unit, and in addition to nanosim, it is possible to use dual SIM in combination with ESIM built into the main unit.
Dual SIMs are very convenient to use, but some people may not be able to use it with confidence, in cases where emergency calls occur.Therefore, I thought about how to use it safely and securely.
The number of smartphones that can use two SIMs, including ESIM compatible, is increasing
It has already been modified in the latest version of iOS (iOS 15).Since 2 or later, it was discovered that there was an emergency news report (110/118/199) when using the dual SIM on the iPhone last September.Specifically, it is used in combination of the SIM of the normal voice call line and the SIM of the data -only line, and it is not possible to make an emergency call if the mobile data communication is set on the data dedicated SIM side.
Using data communication on a sub data dedicated line instead of the main line with a voice call function is considered to be a combination of the main carrier SIM and the cheap SIM of MVNO.This usage is widely introduced as a trick to lower communication charges, and many people should be practicing.
A state where IIJmio's data communication lines are set on the sub with the iPhone.This is a combination that there was something that could not be urgently reported
In the case of the iPhone, it is likely to be a cheap SIM for NANOSIM and the main carrier and ESIM, but in Japan, it is almost only IIJmio when it comes to data communication -only services in Japan, so if you do not use IIJmio ESIM, there is no problem.We tend to be.However, it seems that the same problem had occurred in the case of a voice call SIM on the ESIM side using the data -only SIM on the nanosim side.
Similar problems have occurred in Google's "Pixel 6" and "Pixel 6 Pro" on Android smartphones.After all, it is said that emergency calls may not be transmitted by using "mobile data lines" for data -only SIMs.This problem has not yet been resolved at the time of writing.
The only way to avoid it is to use both SIMs into voice call lines.For example, the main carrier contract is the main, and the data for data is POVO2..If you have a lines with a voice call function such as 0 and Rakuten Mobile, no problem will occur.
Currently, the price difference between voice call SIM and data -only SIM is about 100-200 yen even for MVNO's cheap SIM.POVO2.It seems that there are not always many cases because the data is cheap and can be used for voice calls, such as 0.
In the iPhone and Pixel 6, it is a problem that occurs when using a "trick" of using data communication at a low price, and does not occur in the case of sound SIM.
Xiaomi's REDMI 9T.Recommended models in low -priced ranges that are still cheap, fast, and convenient and three beats.
However, the problem of Xiaomi "Redmi 9T" is slightly different.REDMI 9T is a smartphone that can use two physical SIMs at the same time, but when you send a call, you can select whether to use SIM1 or SIM2, and if you can't urgently report if the previous departure and arrival is SIM2.It is said that there is.
If you set the default of the call to "/", you will select SIM1 or SIM2 each time you send it, but there will be problems in this state.
For example, some people use another phone number for work and private, but have introduced a dual SIM machine to make one smartphone.
In that case, both numbers are incoming, and even if you send them, switching your phone number (work number or private number) for each other should be a common use.In this situation, problems occur if they are recent in SIM2.The avoidance method is to fix the SIM of the transmission settings to either one.
Of course, this would be a problem that should be improved in a software update, but it has not yet been resolved at the time of writing.
If the default of the call is fixed to 1 or 2, it may not be possible to call emergency calls.
REDMI 9T has been around a year since its release, but it has a sufficient performance beyond the frame of low -priced machines, and is still highly recommended.However, until the problem is resolved, it is better to refrain from purchasing the dual SIM function.