There is no voice requirement for IOT card number application.

The reasons why there is no voice demand for this network card number application are as follows:

1. IOT cards can only be used for communication services such as data transmission and short messages, but not for voice calls.

2. The use of 2.IOT card is limited by network signal coverage and base station construction. If the network signal is unstable, or effective network signal cannot be received in some areas or densely built areas, the IOT card will have no sound.

3. The package selection and charging methods of 3.IOT cards are complicated and need to be selected according to specific usage scenarios and needs. If you choose it improperly, there will be no sound.