Jindi SMS robot is free.

Using the network to send, only need to perform the following two steps:

After editing the short message, fill it in the interface of the following software, which is easy to understand, because it will be displayed on the other party's mobile phone in the future.

Copy all the mobile phone numbers you want to send to the other party to the interface above, 1 sec. This is the fastest communication mode in 2 1 century.