Why should I send a message to others? Others are green and I am blue.

Taking Apple's mobile phone as an example, the difference between blue and green SMS:

1. The messages displayed in green belong to the messages of traditional operators, that is, they are generally charged according to the number of messages.

2. The background color is blue SMS, which is a service provided by Apple for its own devices. It sends information through the network for free, that is, iMessage information, whether using wireless network or mobile network.

Short message service (SMS) is a part of unified communication service plan. Users can directly send or receive text or digital information through mobile phones or other telecommunication terminals. The number of characters that users can receive and send short messages at a time is 160 English, numeric characters or 70 Chinese characters.

Short message is a telecommunication service in digital mobile communication system. It is a non-real-time and non-voice data communication service to transmit text or digital short messages through the signaling channel and signaling network of mobile communication system.