# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
2G
2G is short for second-generation wireless mobile telecommunications technology. Second-generation 2G cellular telecom networks were commercially launched on the GSM standard in 1991. Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted; 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS text messages. 2G technologies enabled the various mobile phone networks to provide the services such as text messages, picture messages, and MMS (multimedia messages). All text messages sent over 2G are digitally encrypted, allowing for the transfer of data in such a way that only the intended receiver can receive and read it.
3D Optical Solutions | 光学解决方案
Improves the detection of moving targets, ensures more precise signals can be received from the PIR and allows protection of the area below the detector (creep zone).
3G
3G is short for third generation wireless mobile telecommunications technology. This is based on a set of standards used for mobile devices and mobile telecommunications that use services and networks that comply with the International Mobile Telecommunications-2000 (IMT-2000) specifications by the International Telecommunication Union. 3G finds application in wireless voice telephony, mobile Internet access, fixed wireless Internet access, video calls and mobile TV. 3G telecommunication networks support services that provide an information transfer rate of at least 2 Mbit/s.
4G
4G is short for fourth generation wireless mobile telecommunications technology, succeeding 3G. A 4G system must provide capabilities defined by ITU in IMT Advanced. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, and 3D television.
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