One of the most important upgrades of the iPhone 12 series this year is 5g, and Apple's 5g band is arguably the most comprehensive in the world, with a total of 18 bands. However, there are some problems in foreign countries. When dual cards are used, 5g can only be used. Fortunately, the problem of BOC is avoided perfectly. U.S. carriers have confirmed this problem, and only in a single card state can the iPhone 12 fully support 5g, Not SIM eSIM double card, can only remove the physical SIM card before using 5 G. again
In short,When one card is 4G, the other card can be 5gThe combination of 5 G 4G and 5 G is also the most common collocation of 5 mobile phones.
It should be noted that the iPhone 12 Mini is not a dual card, it is the only single card mobile phone among the four mobile phones, but there is no double card entanglement.