Communication methods at home and abroad from ancient times to the present

Beacon towers generally have several names, such as Pavilion, Pavilion Tunnel, Beacon, etc., and some are also called Yandun. In addition to transmitting military information, it has another function, that is, providing accommodation, protecting safety, supplying horses and food, and contacting important things for envoys. Beacon has become the main contact way for people.

It didn't take long for smart people to discover that using pigeons can help people convey information. Began to domesticate pigeons, tied letters to pigeons' feet and passed them on to the people who wanted to pass them on. After a period of hard domestication, the result was that flying pigeons were used to deliver letters, and the speed was improved many times.

mankind has also created many ways of information transmission, such as ancient beacon towers, golden drums, pennants, navigation lights, etc. These are all ways to solve the problem of long-distance information transmission.

after the mid-19th century, with the development of telegrams and telephones and the discovery of electromagnetic waves, the field of human communication has undergone fundamental and tremendous changes, realizing the use of metal wires to transmit information and even wireless communication through electromagnetic waves, making the mythical "clairvoyance" and "clairvoyance" become a reality.

From then on, human information transmission can break away from the conventional audio-visual way and use electrical signals as a new carrier, which has brought a series of iron technological innovations and started a new era of human communication.

expanded materials

1. With the accelerating integration of industrialization and informatization and the increasing government security investment, the scale of private network communication market has been expanding in recent years, reaching 6.82 billion yuan in 212.

2. According to the calculation of 29 public security departments at or above bureau level in China, 29 mobile base stations are needed; According to the number of police officers in China is 1.7 million, which requires 1.7 million wireless communication terminals; According to the calculation of 1 policemen and 1 police car, 17, vehicle-mounted wireless communication equipment is needed.

Motorola's digital mobile base station costs about 8, yuan, the handheld terminal costs about 4, yuan, and the vehicle terminal costs about 15, yuan. According to the quantitative calculation, the communication capacity of China's public security system's private network is 11.67 billion yuan.

3. According to the calculation of 8 fire engines in a squadron, there are 23,2 fire engines in * *. According to estimates, firefighters in China need 145, wireless communication terminals, 23,2 vehicle-mounted stations or mobile relay stations, with terminal equipment calculated at 4, yuan and vehicle-mounted stations or mobile relay stations calculated at 15, yuan, and the communication capacity of the private network of the fire protection system is about 1 billion yuan.

Baidu Encyclopedia-Communication History of China