China Unicom accepts SMS software.

Terminal-based communication functions such as 1. SMS can only be realized if both parties open the same client software, so it is impossible to communicate with traditional telecom operators at present. This is really a problem. Therefore, the client program must also be installed now.

2. If the other party is not a smart machine, it is impossible to install the client program. Of course, some custom machine have built-in available clients.

3. If they are all smart phones, there are too many. I have used Mi Chat, WeChat and viber, all of which are good. As long as one function is updated, others will be updated. The key is what your friends are using. If they use rice chat, you can't communicate with each other on WeChat. So you may get a more popular installation.

4, neutral this machine is good.