ADSL access point: the pros and cons, how to choose, operation

ADSL access point - the user equipment (modem) is connected to an analog telephone line for receiving and transmitting data.

ADSL modems differ by:

• Dial-up modem - has no built-in DHCP server, that is only possible to connect 1 PC;
• Router - equipment with a web interface, DHCP server - connect multiple user devices for UTP cable (twisted-pair) depending on the number of ports on the LAN router or wireless manner WIFI. When using WIFI number of connected subscribers 32.

ADSL device

The technology implies a use of one channel for telephone and internet access. DSL provides high-speed Internet access of up to 8 Mbit / s.

ADSL - is asymmetric technology. This means that the flow rate of the outgoing data from the user is less than the flow of incoming data. To use the Internet, it is a suitable option, the user receives the information from the Internet, and gives much less.

Thanks to digital signal processing, the amount of information is compressed for faster data transfer. Due to the excessive length of the telephone line may be a signal supply problems. Because of this, the modem should work, maintaining a load, for a satisfactory dynamic range and reduce noise.

The main thing - is the transmission of multiple signals over a single line. This option appears by using the method of separation of the telephone line the strip, in which it is divided into several frequency bands.

Due to this, ADSL provides simultaneous transmission of different threads on the velocity signal. Telephone, in a network which is ADSL- modem is not interrupted.

Connect asymmetrically, so to get an idea of ​​the speed internet connection, you need to to understand that the latter is not always the same, because the speed of outgoing traffic is different from the speed included. Incoming traffic, because of its demand is accepted at a higher rate than is given to the outgoing.

Largely receiving speed and efficiency of traffic is dependent on the subscriber line to which the modem is connected. This applies to the cable volume, presence or absence of bridged taps on the network, and the main line extension. The more long lines and stronger than the signal frequency increases, the more the attenuation of the signal increases. Reverse effect creates thickness and diameter of the cable.

In the standard wire thickness of 0.5 millimeters, maximum length limit lines for normal operation and functionality - five and a half kilometers. It is not necessary to connect an ADSL modem to a standard telephone distributive wires - called in the "noodles" of the people. This will slow down the transfer of data. Requires copper twisted pair wire or P-field 274m.

When using frequent channel separation mechanism, unlike echo cancellation, low velocity flow a channel for data transmission is immediately after the frequency band used to transmit telephone communication.

High-speed channel, and has a different arrangement. It is located on the higher frequencies. The frequency band in direct proportion to the number of bits that are transmitted one signal.

Frequency division channels, and echo cancellation to each other have advantages and disadvantages:

• echo cancellation difficult to fulfill
• Performance Internet connection up to two decibels, using the echo cancellation
• At speeds echo suppression prevails, since the frequency separation of channels leads to attenuation of the signal
• By using frequency division multiplexing, no effect of NEXT

How to choose the ADSL access point

First, decide on how many users need the Internet. If a PC using a simple wired or USB modem with a single LAN port.

In the case of USB modem, a network adapter is not required, the device is powered by usb port.

In the case of Ethernet ADSL router selection with 4 or more ports, look at the passport data device maximum speed LAN ports - standard is 100Mb / s, expressed as megabytes - 12.5 MB / sec.

If you plan to use more than one user is selected as ADSL WIFI access point router with 4 LAN (Ethernet) ports. Pay attention to data transfer mode WIFI - in all 3 modes b / g / n (indicated on the box and in the passport data).

• b - An obsolete standard, maximum 11 Mbit / s;
• g - outdated standards, but the maximum data transfer up to 54 Mbit / s;
• n - The current standard, a maximum of 600 Mbit / s, but it depends on a router model - the budget is 150 Mbit / sec.

Please note that the rate listed in the aggregate, that is, taking into account the incoming and outgoing traffic. With increasing number of users, the router speed is evenly distributed between them regardless of the method users connect to the access point - data exchange between the user device (PC, smartphone, tablet) and router.

Pay attention to the internal memory. The more megabytes of internal memory on the device, the greater the load the modem is able to withstand without knocking operation of the Internet. It is recommended to purchase a RAM memory of at least 64MB FLASH memory, and at least 32Mbayt.

Advantages and disadvantages

dignity

USB modem:

• The lack of clutter.
• It does not require power supply.

Ethernet and WIFI modem (router):

• Having a web interface to configure the device.
• The ability to remotely connect to the router.
• Connection to the internet automatically when you turn on the router - no need to configure on the PC Internet connection.
• DHCP server assigns an IP address connectable devices - connected users are combined into a single LAN.

disadvantages

USB modem:

• Software to install.
• No web interface.
• Requires a PC configuration to connect the Internet connection (no router mode).
• The speed of data transmission between the PC and modem is dependent on the speed and the state of USB port, in practice, not exceed

100Mbit / sec.

Ethernet and WIFI ADSL Router:

• Budget models cut speed.
• In case of overheating the router hangs.
• After 2-3 years of use WIFI module periodically stops responding (in some cases, the problem is solved router firmware).

Exploitation

Before setting up an access point, make sure that the Internet service provider or the operator of the telephone network supports the technology.
ADSL access point connected to a telephone line network, outlet and computer. Then you need to install on your computer a special driver, which drive comes bundled with the access point.

As with any electronic device, in dealing with the modem role security. It is recommended to get acquainted with a few rules that will help you extend the life of your equipment.

Installation device to conduct in a place protected from moisture and heaters.
Do not connect the power supply to the other models of routers.

Do not place near the electromagnetic field! Electromagnetic fields influence the device, which causes a malfunction.

You can not have the access point (WIFI router) close to sensitive devices electromagnetic radiation, emits elektrovolny as affecting - a pacemaker, medical equipment.

Do not disassemble the device yourself if it is under warranty, the company has the right to withdraw from the obligations of the insured event, after disassembles the equipment.

If the device is a button for automatic switching on and off, it is necessary to complete the work to press the button and not to disconnect from the mains power supply pulling. This leads to the malfunction of the modem.