Why can't Mi Tu Watch send text messages?

The main card that binds the mobile phone watch is down. A telephone watch is a small mobile phone that looks like a watch and is usually worn on the wrist. Mi Tu Watch can't send SMS because the main card that binds the mobile phone watch is down. The operation mode of telephone watches is generally touch operation, and some models are key operation. Its characteristics are simple and portable, small and light, and free hands. Satisfy children's playful nature. The core function of telephone watch: two-way call function.