In the field of network operation in the telecommunications industry, the phenomenon of monopoly is relatively common, taking the United States as an example, AT&T is the American Telephone and Telegraph Company, which occupies 80% of the US telephone market.

In 1984, AT&T was forced to spin off due to an antitrust lawsuit by the U.S. Department of Justice.

There is a rumor circulating that before AT&T was spun off, IBM was the second largest company in the United States. After AT&T was spun off into seven companies, IBM's ranking became eighth.

This shows how far the monopoly phenomenon reached at that time.

The equipment manufacturing field in the telecommunications industry is also full of powerful people, and there is the shadow of national capital to varying degrees.

Of course, latecomers are not without the opportunity to be among them, because the world's telecommunications industry is ushering in a new round of technological upgrades.

The Public Switched Telephone Network, or PSTN, is the largest network in the world, dating back to 1876, when Bell invented the telephone.

Among the two major components of PSTN, the transmission system is mainly composed of transmission equipment and cables.

At present, the technology of transmission equipment is mainly carrier multiplexing, and the cable is mainly copper wire, but the corresponding latest technology, the synchronous digital system SynchronousDigitalHierarchy, that is, SDH and optical fiber, is gradually beginning to emerge.

Another major component of the PSTN switching system, the equipment used is mainly telephone exchanges.

With the progress of electronic technology, the telephone exchange has undergone a magnet, step-by-step, vertical and horizontal system, and has developed to the current stage of program-controlled exchange.

In 1970, France opened the world's first program-controlled digital telephone exchange, which adopted time division multiplexing technology and large-scale integrated circuits.

Since then, other countries have vigorously developed and quickly followed suit.

In the 1980s, it was the period when program-controlled digital telephone exchanges began to be popularized in the world.

In PSTN, a switch that is connected by a user through a direct connection is called a terminal office.

At present, analog signals are mainly used for transmission between users and terminal offices, and the system that uses digital signals exclusively to connect users and terminal offices, the Integrated Services Digital Network (ISDN), has emerged, such as Deutsche Post's decision in 1979 to digitize all local telephones in Germany.

Originally, after the 1990s, ISDN became widespread on a large scale in European countries such as Germany and Japan in Asia, but in the United States, ISDN became a chicken rib because of poor market promotion and lack of price advantages.

As for the Dragon Kingdom, although the telecommunications industry is developing rapidly, it needs a process after all.

Therefore, when ISDN was very common in European and American countries, Longguo introduced this technology and began to install local equipment in a few pilot cities.

At this time, the Asymmetric DigitalSubscriberLine, or ADSL technology, has matured and been promoted to the market.

So invisibly, the dragon country avoided the big pit of ISDN and directly entered the era of ADSL.

When the telephone system was first designed, it was mainly used to transmit voice calls, and for economic considerations, it was designed to transmit frequencies ranging from 300Hz to 3.4KHz.

Copper cables, on the other hand, can actually provide higher bandwidth, at least from the lowest frequency to 200-800KHz, depending on the quality of the circuit and the complexity of the device.

Unlike fully digitally connected ISDN, DSLs can provide a variety of additional data services in addition to basic calling functions by utilizing additional frequency bands higher than 3.4KHz on telephone lines to transmit data, as ISDN does.

The idea of DSL can be traced back to 1988 when an engineer devised a method to load digital signals into unused frequency bands of telephone lines, enabling data communications on ordinary telephone lines without compromising voice service.

However, Bell's management was not enthusiastic about the technology, as it would be more profitable if the user installed two lines.

In the late 1990s, Bell woke up from a dream when cable companies began providing broadband Internet access using biaxial coaxial cables in their cable networks.

Realizing that most subscribers would definitely give up installing two phone lines to access the Internet, Bell finally moved out of the DSL technology they had been discussing for 10 years to compete for the cable network's broadband market share.

For a long time, DSL technology and the cable modem CableModem, or C.M., became a major competitor in the European and North American markets for broadband access services for home users.

As a reborn, the development trend of the telecommunications industry in the next few decades is naturally under Tang Huan's control.

Although the threshold for this field is very high, the rapid progress of technology also means a change in the rules, and there are countless examples of cable TV companies using their own networks to challenge the position of traditional telecom companies to provide Internet access services in the future.

The breakthrough that Tang Huan thought of was the point in the huge PSTN - program-controlled digital telephone exchanges, especially the PrivateBranchExchange, a PBX that specializes in serving specific enterprises or institutions.

The main task of the PBX is to complete the telephone exchange between the extensions in the system and with the PSTN, the most obvious advantage is to reduce the telephone charges by handling the line conversion within the system, and can also add some service functions that are not provided by the telephone company, such as intelligent hunting, user calling, dialing extensions, etc.

In the PBX structure, the single-chip microcomputer used for data processing and control is Tang Huan's housekeeping skill, and as for the R&D engineers of other technologies, there are a lot of companies available for poaching.

Besides, didn't Huawei start as a switch, Tang Huan has too much experience to learn from.

On the other hand, the most practical way to connect a PC to the PSTN is probably a modem.

Back in 1962, AT&T released the first commercially available modem, the Bell 103.

By 1978, American Dennis Hayes and his partner Dale Heatherington had successfully sketched out the prototype of a smart modem at the dinner table. That same year, at the age of 29, Hayes founded He's Computer Products in Atlanta.

Dennis Hayes loves Chinese culture, not only gave himself the Chinese name He Danyi, but also married a Chinese Ningbo.

In 1981, Danyi's company successfully developed the Hayes SmartModem, which is a major step forward for the standard smart modem in the true sense of the word.

Before the advent of smart modems, almost all old-fashioned modems had to manually dial the other person's number on the telephone in order to establish a connection, and then place the handset in the AcousticCoupler, or sound coupler, which is a device composed of two rubber cups used to convert between sound and electrical signals.

With a smart modem, in addition to eliminating the need for a sound coupler, more importantly, you can connect the smart modem directly to a standard telephone line or outlet, and then the computer can automatically connect the phone and dial the number.

It can be said that this change greatly simplifies the installation and use of the electronic bulletin board system, i.e. BBS.

It turned out that time and space, although He's was finally abandoned by the market, but it relied on its own first-mover technology advantages, occupied a dominant position in the field of modems for a long time, and its proposed AT instruction set has almost become the industry standard, and many other brands of smart modems will deliberately write on the packaging that Hayes-Compatable is compatible with He's standard.

Tang Huan did not pay special attention to this industry at first, and he planned to wait for the research and development of the second-generation computer of Fangyuan to be basically finalized, and then buy it from He's according to the needs.

But in order to develop a fax server, the smart modem was piggyback on a prototype, and it would be a shame not to use it to the fullest.

And if users use Fangyuan computers and smart modems at the same time, and let network operators use telephone exchanges developed according to their own design goals, maybe the early dial-up Internet access method in the previous life will appear more smoothly.

The only thing worth worrying about is that the R&D and operation of telephone exchanges must have burned a lot of money in the early stage, and under the principle of isolation of non-related industries formulated by itself, I don't know whether the incubator of Zheru America can afford this task only by relying on its own ability to absorb money.

"You say, is this kind of digital fax machine that we have newly developed attractive to a wealthy man like the Xiangjiang Police Department?" Tang Huan turned his head sideways and asked Zhou Weikun beside him.

"In terms of functionality alone, it's a huge advantage, but I don't know what kind of strategy it is in terms of pricing." Zhou Weikun groaned, "But you can follow Feng Xingjun's routine, first pull to our boat, and then squeeze out the profits step by step." ”

"Your cooperation is getting more and more tacit." Tang Huan shook his head and smiled, "In this way, we have to work the control of product costs, and I just want to go to Japan to see if Sharp can produce a batch of OEM, and now Japanese companies are the most enthusiastic about moving closer to us." ”

The issue of digital fingerprinting was discussed until the end of the day, and the technical solutions were finally finalized one by one.

Tang Huan let out a sigh of relief, returned to his office, and drank the tea in the cup with his neck tilted.

After that, Tang Huan began to write the research and development plan of the program-controlled digital telephone exchange, until his stomach growled, and he remembered that he had not eaten dinner.

Secretaries, bodyguards, there are a lot, but no one cares if he is hungry or not, Tang Huan complained and picked up the phone, forgetting that he himself had made a pact not to easily disturb his work.

Tang Huan originally wanted others to prepare dinner for him, but he remembered Zhao Yazhi, who had been mixing oil with his honey in the past few days, so he called the apartment.

Soon, the phone was connected, and Zhao Yazhi's gentle voice came, Tang Huan perked up and asked, "Is the apartment furnished?" I haven't eaten dinner yet, can I come to your place to settle it? ”

"Then you can come here." Zhao Yazhijiao agreed with a smile.

"There's a door." Tang Huan was overjoyed in his heart, and it seemed that both physically and mentally could have a full meal again.

The high-end apartment that Tang Huan gave to Zhao Yazhi was located near the broadcast road where TVB was located, and he quickly rushed over.

"Let's cook noodles and eat them, it's fast and convenient." Zhao Yazhi leaned out of the kitchen and said to Tang Huan, who was changing shoes at the door.

"Okay." Tang Huan agreed, walked into the living room and looked at the layout, it was very elegant, giving him a feeling of home, and the heat in his heart couldn't help but cool down slowly when he came, and his heart became warm.

"My personality is really complicated." Tang Huan muttered to himself, sat comfortably on the sofa, and asked casually: "Ah Zhi, I'm going to Japan, you can follow the tour by the way." ”

"No, I still had the ideal of traveling around before I became a flight attendant, but now it's long gone." Zhao Yazhi directly refused, and made a grimace, "Moreover, I'm afraid that you will come nonsense, and when the time comes, you will have to call the heavens and the earth to be ineffective." ”

"Hey, it's so faceless, it seems that you have to use it." Tang Huan stood up, with a threatening look on his face, and forced over.

"Don't make a fuss, I'm cooking noodles, and I don't have to eat when it's paste." Zhao Yazhi smiled and hurriedly dodged.

"Eat you first, then noodles." Tang Huan snorted and hugged Zhao Yazhi's slender waist, and there was a whining sound in the kitchen.