Why can't I send short messages when I change my 3g card?

There may be incompatibility between 4G card and 3G mobile phone. It is suggested to switch back to the original 3G card or put it into a 4G mobile phone.

Reason:

1, the telecom 4G network standard refers to TD-LTE and FDD-LTE, which integrates 3G and WLAN and can transmit high-quality video images.

1. Telecom 4G cards can be used in 3G/2G networks that are backward compatible with telecommunications, so telecom 4G cards can be used in 3G mobile phones.

2. Telecom 3G mobile phones can only use 3G/2G networks, not 4G networks.

3. Telecom 4G may use its calls, text messages, etc. When you plug in a 3G mobile phone, a 4G card is best used on a 4G mobile phone.