The way to judge whether the small tail board is broken is to remove the phone battery and charge it. If the screen is on, it means it is not broken. If the screen is not on, it means that the small tail board is faulty.
Mobile phone is a portable telephone terminal that can be used in a wide range. Its full name is mobile phone or wireless phone. At first, it was just a communication tool. In the early days, it was commonly known as Big Brother in China. The mobile phone was first developed from the battlefield mobile phone manufactured by Bell Laboratories in 1940. Later, Martin Cooper, an engineer of Motorola, invented the world's first commercial mobile phone in 1973. In addition to typical telephone functions, modern mobile phones also include more functions such as camera, GPS and Internet connection, which are generally called smart phones. In terms of communication technology, modern mobile phones have also made significant progress. When Cooper calls the world's first mobile phone, he can use any electromagnetic frequency band. In fact, the first generation of analog phones differentiated different phones of different users by different frequencies. The GSM system, the second generation mobile phone, distinguishes users by extremely small time difference. Today, the frequency resources are obviously insufficient, and the number of mobile phone users is growing exponentially. As a result, the newer CDMA technology that distinguishes different machines by different codes came into being. The mobile phones using this technology not only have better call quality and confidentiality, but also reduce radiation, which can be called "green mobile phones".