At 10 a.m. on January 10, the US National Science Foundation (NSF) announced the formation of the NSFNET network to connect six supercomputer centers in the United States through 56kb/s communication lines to achieve resource sharing.
When Li Zetian heard the news, his heart moved, and he immediately asked Dongfang Yuqin to collect more detailed information.
The next day, Dongfang Yuqin handed over a detailed document about NSFNET to Li Zetian.
After reading the materials, Li Zetian said: "NSFNET adopts a wide area network with a three-level hierarchical structure, and the entire network system consists of a backbone network, a regional network and a campus network. The hosts of each university can be connected to the campus network of the university, and the campus network can be nearby. Connected to the regional network, each regional network is connected to the backbone network, and the backbone network is connected to ARPANET through high-speed communication lines. In this way, any host in the school can access any supercomputer center through NSFNET and ARPANET to achieve Information exchange between users!"
Dongfang Yuqin nodded: "Yes, Mr. Li, you are absolutely right!"
Li Zetian laughed and said, "Since the National Science Foundation has begun to act, it is time for us to act!"
Dongfang Yuqin didn't know Li Zetian's plan very well, so she showed a hint of doubt: "Mr. Li, what are you going to do?"
"Backbone network, we don't have the right to build and operate it now, but..." Li Zetian paused and said, "We can build a metropolitan area network connecting ordinary people!!!"
After all, Dongfang Yuqin has been with Li Zetian for so long, and it is easy to communicate with one point. He was surprised: "Mr. Li, you mean, we are buying local telephone companies and borrowing their telephone lines to connect to the Internet?"
"Yeah, that's it! As long as there is a modem (Modem), users can dial-up Internet access."
Telephone lines can only carry analog signals, while computers can only recognize digital signals.
A modem is a device for signal conversion between a computer and a telephone line, and consists of a modulator and a demodulator. At the sending end, the modulator is a device that modulates the digital signal of the computer (such as files, etc.) into an analog signal that can be transmitted on the telephone line; at the receiving end, the demodulator converts the analog signal into a digital signal that the computer can receive. .
Data communication between computers can be achieved through modems and telephone lines.
Optical fiber does not need to rely on analog signals, but directly uses digital signals, so the speed and bandwidth are large, but the construction cost of optical fiber lines is very high. In the 1980s and 1990s, telephone lines were basically used to access the Internet. The decrease of the transmission speed and the increase of the transmission speed have gradually become popular.
At present, Li Zetian will not abandon the basics and spend a lot of money to lay optical fibers. Instead, he will first seize users and then update the hardware level.
This year is definitely very lucky for Li Zetian. The U.S. Department of Justice is preparing to break up AT&T under the Antitrust Act, splitting it into a new AT&T company (specializing in long-distance telephone business) and seven local telephone companies (the "Bell Brothers") that inherit the parent company's name. The US telecommunications industry will enter the era of competition from now on.
Before the split, AT&T almost monopolized the intrastate, interstate and international telephone business in the United States, and was a veritable super giant company. Its turnover in 1983 exceeded that of the other three major US companies (Exxon, Mobil, General Motors) combined. And these three companies are the top 30 companies in the top 500 companies, so there is no need to say more about AT&T.
Right now is a heaven-sent opportunity for Li Zetian to enter the telecom industry! ! !
In fact, Li Zetian has never entered the telecommunications industry before, just waiting for AT&T to break up. This antitrust lawsuit started in the early 1970s and lasted for more than 10 years, and AT&T is obviously powerless.
At this time, Li Zetian instructed: "Dongfang Yuqin, pay close attention to AT&T's anti-monopoly case, and notify me as soon as there is a result!"
"Okay, Mr. Li."
Li Zetian thought for a while, then stood up from his chair, "Go to Galaxy Network Company. I told Tian Shuai before that Galaxy Network Company is going to develop modems. I wonder how the development is going now?"
Dongfang Yuqin nodded and immediately followed behind him.
…
More than an hour later, Li Zetian and Dongfang Yuqin rushed to the Galaxy Network Company, and then called Tian Shuai and Zhang Yan to the office.
Li Zetian said: "The National Science Foundation (NSF) is going to set up the NSFNET network, you know?"
"Well, I see!" The two nodded.
Li Zetian said: "As long as NSFNET is established, we can use modems to realize the function of networking with telephone lines. How are modems developed now?"
Tian Shuai said: "A quarter is completed."
"It's so slow??" Li Zetian was puzzled. The Galaxy Network Company has a lot of talents, and the research and development efforts are strong, so the development speed should be very fast.
Zhang Yan explained at this time: "Mr. Li, don't worry, there is a reason for the slow development progress. Currently, the fastest commercial modem is Bell212, which uses a more stable item shift keying technology to convert data into The rate is increased to 1200 bit/s.”
"What is item shift keying technology?" Li Zetian asked.
"Oh, the shift keying technology is a technology that uses two tones to represent 1 and 0..." Zhang Yan briefly introduced it, and then continued, "At first, when we were discussing, we also planned to use Bell212 similar to Bell's. system, but the product produced by doing this is not much better than Bell212. Mr. Li, you are definitely not satisfied, so we overturned the original plan and decided to develop a faster modem. After a period of research and discussion, we decided to Using a new scheme, the data rate of the modem can be increased to 2400bit/s."
Li Zetian was shocked when he heard the words, and asked curiously, "What plan?!"
"The system is also similar to Bell212, but we use bidirectional signal sets on 4 pairs of dedicated lines to achieve 2400 bit/s."
Sounds a bit ignorant!
However, Li Zetian understood it. The two-way signal set has naturally doubled the speed. Of course, it is easier said than done, and it is understandable that the development progress is a bit slow.
Li Zetian thought about it, it will take a long time for the US National Science Foundation (NSF) to set up the NSFNET network, and it will take a long time for him to acquire the local telephone company. There is enough time for Galaxy Network to develop modems.
"By the way, Galaxy Network's research and development of optical fiber can't stop for a moment! The broadband of the telephone line is too small, and the data transmission rate is too low, and it will definitely be replaced by optical fiber. Optical fiber products with very powerful data transmission capabilities!" said Li Zetian.
Tian Shuai and Zhang Yan looked at each other and nodded.
"Don't worry, Mr. Li, Galaxy Networks will definitely attach great importance to the development of optical fibers!" Tian Shuai assured.
Don't look at a small optical fiber, but it involves many cutting-edge technologies such as materials and optics, and it is still very difficult to develop.