Use ADSL to build an affordable office network

What is ADSL?

ADSL is the abbreviation of asyuncrical Digital Subscriber Loop (Asymmetric Digital user Loop. ADSL is a high-speed broadband technology that runs on the original ordinary telephone line. It uses existing telephone copper wires to provide users with asymmetric uplink and downlink transmission rates (bandwidth ). The so-called "asymmetric" is mainly reflected in the differences between upstream and downstream speeds. Uplink (from the user to the network, that is, the upload) is low-speed transmission, only 1 Mbps; downlink (from the network to the user,
That is, download) for high-speed transmission, up to 8 Mbps. It was initially developed for the video-on-demand service. With the development of technology, it has gradually become a more convenient broadband access technology, which is valued by the Telecom Department. Through the set-top box of the network TV, many network applications that were previously unable to be implemented at a low speed can be realized. ADSL can make full use of the existing telephone network. As long as the ADSL device is installed at both ends of the line, it can provide users with high-speed broadband services. It is a very cheap broadband network access method. It overcomes the bottleneck of the traditional access method in the "Last Mile" and achieves broadband access in the true sense.

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What is the bottleneck of "last mile?

With the vigorous development of the Broadband Access Project, the computer-fiber-optic Internet is rapidly changing our traditional economic and traditional concepts. Smart residential buildings and smart office buildings will emerge soon. At present, the bottleneck of domestic applications lies in the end user process. During the construction and development of smart housing, real estate agents are often troubled by factors such as last mile access, cost, technology, investment, and return on investment. That is to say, no matter how wonderful the Internet world is, the last mile of access has become a bottleneck restricting the development of broadband Internet.

Why ADSL?

ADSL, a broadband access technology, has the following features: it can directly use existing user telephone lines to save investment; it can enjoy ultra-high-speed network services to provide users with asymmetric upstream and downstream transmission bandwidth; it saves costs, you can call the Internet at the same time without affecting each other, and you do not need to pay additional phone fees when accessing the internet. The installation is simple, and you do not need to apply for additional lines. You only need to install an ADSL Modem on a common telephone line, install the NIC on your computer.

How to build an ADSL Network?

Building an office network requires the least investment to maximize the benefits. There are two ways to connect to the Internet through ADSL: one is to configure a computer in the LAN into a server to control the Internet access of all the computers in the network. This computer must have two NICs, one controlling inbound data, and the other connecting other computers in the LAN through the Hub. This connection method is called shared Internet access with two NICs. The other is to directly connect the ADSL Modem to the Hub, and then the Hub distributes data to various computers. In comparison, the first access method requires one more Nic, and the advantage is not too obvious. The second access method only requires one Nic for each computer. Therefore, we decided to use the second access method.

ADSL office network component connection

Hardware configuration: The selected host is equipped with a Pentium III 800 MHz CPU, 8.4 MB memory, and the remaining hard disk space is greater than GB. One ADSL Modem and one Hub each; three 10 m NICs; one separator and N network cables (assuming there are three hosts in the network ). For the minimum configuration required by China Telecom, see the table.

Step 1: Install the NIC. Insert the purchased 10 m Nic into the white PCI slot of the host. Because the transmission speed of the ADSL Modem is 1 Mbit/s/8 Mbit/s, the serial port of the computer cannot reach this high speed (the current USB interface meets the speed requirements, and there is also the ADSL Modem of the USB interface on the market ). This Nic is used to establish a high-speed data transmission channel between the computer and the modem.

Step 2: connect to the hub. Connect one end of the network cable to the computer Nic and the other end to the non-Uplink port of the Hub.

ADSL Modem connection

Step 3: connect the separator and ADSL Modem. Connect the Uplink port of the Hub to the Ethernet port of the ADSL Modem using a network cable. Connect the line (DSL) Port of the ADSL Modem to the output end of the splitter. Finally, the line input of the separator must be connected to the telephone line. Note that this separator must be installed on the telephone bus, that is, the interference caused by network data has been separated from the analog signal of a normal phone before the phone is connected, it would be useless if the phone is disconnected.

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What is a signal separator?

The signal splitter is used to separate high-frequency digital signals from low-frequency voice signals in telephone lines. The low-frequency voice signal is sent by a separator to the telephone to transmit normal voice information. The high-frequency digital signal is connected to the ADSL Modem to transmit Internet information and VOD programs. In this way, the quality of your voice will not be affected by the interference of high-frequency signals when you use the phone, or the speed of the Internet will not be affected by the connection of the voice signal. You can imagine surfing the Internet through a computer while chatting with friends over the phone, and watching wonderful on-demand video programs through a TV set with a set-top box.

Subtotal

In this example, when the ADSL Modem and Splitter are installed, the Telecommunications Department has already received the fee, which is negligible. The rest are the Hub, Nic, and network cable. In this example, there are only three computers, and a Hub with a port of 5 is enough. The D-Link brand is famous and the quality is guaranteed. The price is about 300 yuan. As for Nic, D-Link PCIe card contains RJ-45 and BN dual-port Nic, price only 75 yuan, stable and reliable performance. In this example, the network cable is about 20 meters, which is calculated as 2 yuan per meter. A total of 40 yuan is required. Total price: 300 + 75 + 40 = 415 (RMB ). Investing in a small office network only costs 415 yuan. For most small-sized shared office networks with low requirements, it is very economical.

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