Why can some short messages send so many words?

Each message is 70 words on the Internet, but this is for China people! If it is changed to a pure number, it should be a numeric character of 160!

But for different mobile phones, each text message on this machine can write many numbers, and the upper limit is different. Send it to the other party's mobile phone after passing through the network, and send it in strips according to the upper limit of the network. The upper limit of each acceptable character of the other party's mobile phone is the upper limit of his mobile phone. Accept it in strips!