Have you watched the recently popular "12 Hours in Chang'an"? After the author researched the watchtower system, I fell into endless thinking... "Chang'an 12 Hours" with a score of 8.6 on Douban is not too harmful! Yeah, I've been gone for a month, just because I'm on a show... I'm running out of free time, really. (Not because I'm lazy) Finally, the show ends today, and I can resume the update! As a drama fan + technology house, today, I will dig deeper for you, the communication setting in this drama - Wanglou. It appeared in the first episode. "This is Wanglou, it will be of great use to you today." This was the first thing Tan Qi explained to Zhang Xiaojing. In fact, it is a communication system that transmits messages in Chang'an City. There is a watchtower every 300 steps in the city, and the news can spread throughout Chang'an City in a flash. As soon as I saw this, I was excited! Eh? Isn't this a 12-bit communication system! You see, he has two rows up and down, a total text message service of 12 grids, and each grid can be turned on or off. If the light is 1 and the light is off is 0, then in the following figure, 12 bits can be expressed as: 101011 101100 . After we have the binary code, we can encode and decode , that is, to correspond "code" and "word". In modern computers, the most basic is to use ASCII code. The following is a comparison table: letters, numbers and symbols can be represented. For example, O is 0100 1111, M is 01001101, and G is 0100 0111. Then, Li Jiaqi's mantra, expressed in binary is: 0100 1111～ 01001101～ 0100 0111～ In fact, there are already a lot of 12-bit bits. The ASCII code above is actually only 7 bits. (It looks like 8 bits, but the first bit is all 0) Then 12 bits can actually represent 2 to the 12th power, which is 4096 Chinese characters. According to the "List of Commonly Used Characters in Modern Chinese" published by our China in 1988, there are only 3,500 commonly used Chinese characters, which can cover 99.48% of daily needs, so 12 characters are completely enough. The Chinese character encoding of today's computers is more commonly used, such as Unicode. The following is a comparison table. After I carefully studied other party to pass it again. If you have a lot of bits that can be used for error co "Twelve Hours", I found that there are actually two kinds of watchtowers in the play! One is the small watchtower above, with two rows