First of all, it may be that the 5G mobile phone you buy is not a full Netcom mobile phone and does not support the telecom card, and second, the geographical location of your mobile phone may not be within the coverage of the telecom 5G signal base station, so it can not receive the 5G signal of the telecom card, only the 4g signal can be received. If your mobile phone is a 5G mobile phone, and the area that supports the telecom card is also covered by 5G signal base stations, it may be that your mobile phone card is faulty, and you can replace it with a new mobile phone card
Possible causes :1. The 5g switch is not turned on on the user's mobile phone terminal. 2. There is no 5g network coverage in the place where the user is located; 3. The preferred network mode of the user's mobile terminal is not set to the NSA SA mode.
There are two reasons why phones don't display 5G networks. First, because the current location is not within the coverage of 5G signal, even if the 5G mobile phone and 5G mobile phone card are used, the mobile phone will still display 4G network; Second, the phone's 5G network switch may not be turned on.
I hope the above answer can help a lot of friends, thank you for your support and encouragement, I will continue to try my best to answer all your questions for you.