What are SMS and EMS SMS?

SMS is the abbreviation of short message service, which is a technology that can send and receive text messages using mobile devices. The maximum length of a short message is 160 bytes (about 80 Chinese characters, so short messages are usually limited to 70 Chinese characters because other related information has to be sent), which is equivalent to the space occupied by a voice call of about 1 second, so its communication cost is very low. The transmission of messages is always relayed by SMSC (Short Message Service Center) outside GSM. Similar to e-mail, SMS messages are only related to the user terminal and SMSC. The well-known GSM and later networks provide support for SMS.

EMS (Enhanced Message Service) is an enhanced version of SMS, which was put forward by people at the beginning of 2 1 century. The function of this service is to send simple images, sounds and animations in addition to text. At that time, there was the concept of MMS, but due to the limitation of GPRS network or CDMA 2000 1X(2.5G network), SMS was designed as a transitional version from SMS to MMS. EMS can be sent in GSM network, which should be said to be a good technology for the transition from 2G network to 2.5G network. The biggest change in EMS support is the operator's billing system, because the number of words occupied by images, sounds and animations may vary greatly, and operators need to carefully measure them.

MMS is the abbreviation of multimedia message service, which means multimedia short message service in Chinese. This service is based on the standards of 3GPP and WAP forum. In the aspect of multimedia short message service, with the support of GPRS network or cdma2000 1X network, WAP wireless application protocol is used as the carrier to transmit video clips, pictures, sounds and words. It supports various high-speed data services, such as voice, Internet browsing, e-mail, conference TV and so on. Realize instant multimedia information transmission from mobile phone end to end, from mobile phone terminal to Internet or from Internet to mobile phone terminal. The emergence of this service can replace some functions of e-mail, and can be used as an electronic postcard to provide extremely rich services. The biggest obstacle to the development of this service is the speed limit of the current 2.5G network. Slow network speed directly leads to high tariffs. Although the price has dropped a lot, it is still unbearable for most users.