Network based on xDsl modems. Network based on xDsl modems Possible malfunctions and solutions

The DSL 2500U modem from D-link is another router of the DSL family, outwardly not much different from its older brother, but significantly inferior to it in terms of technical characteristics.

Router d link dsl 2500u: specifications

A detailed list of technical characteristics of the d link dsl 2500u router can be found in the following illustrations:

Brief overview of the d link dsl 2500u router

Like most routers, there are a number of indicators on the front panel of the d link dsl 2500u router that inform the user about the following aspects of the device’s operation:

• "POWER" - the presence of power on the router;
• "STATUS" - the status of the router and possible errors in the system (if the indicator is inactive or, on the contrary, is constantly lit);
• "LAN" - connection and activity of network devices;
• "DSL" - DSL synchronization status;
• "Internet" - informs about the presence of an Internet connection and possible errors (if the indicator is red).

There are four elements on the back panel:

• "DSL port" - for connecting the router to a telephone line;
• "LAN port" - for connecting network devices;
• "Reset" - a button to reset the settings of the d link dsl 2500u router to factory settings;
• "5V=1A" - connector for connecting the battery.

Installing and connecting a Rostelecom modem

The principle of installing and connecting the d link dsl 2500u router is elementary and is no different from other models:

• in a well-ventilated place away from heating elements, protecting the modem from direct sunlight;
• turn off the router (dsl port) connect to the Internet line (telephone cable or cable coming from the splitter);
• to the "LAN" port;
• connect the power supply and turn on the router.

Setting up an Internet connection on a d link dsl 2500u router

To gain access to the web interface of the router, use the address 192.168.1.1, which must be entered in the address bar of any Internet browser (the default login and password are "admin").

The illustrations below correspond to the latest firmware version 1.0.50.

When you first enter the router interface, a window will appear asking you to make the initial settings of the router.

You can either use the "Settings Wizard" - in order to configure the d link dsl 2500u router in semi-automatic mode and select only the main parameters, or "manual settings" - in order to "carefully" set all the necessary parameters.

Within the framework of this article, we will consider in detail exactly the manual configuration of the modem - in order to have a more complete picture of the network created by the router.

Setting up a d link 2500u modem using the Setup Wizard

The sequence of actions for automatic configuration of the router is shown in the following illustrations:

Advanced settings for the d link 2500u router

To create an Internet connection manually, open the "Network" menu, the "WAN" section and click "Add".

You will see the "Creating a WAN connection" window: here in the "Connection type" line you need to select one of the proposed options, based on the data that the provider indicated in the contract (the same applies to filling in the username, password and atm interface).

Bridge

• enter the value of "VPI" and "VCI" - depending on the region and service provider;
• check the boxes "NAT" and "Firewall".

"PPPoE" or "PPPoA"

Here, in addition to the parameters described above, you should specify:

• "Username" and "Password" (twice);
• if desired and necessary, enable the options "Connection on demand", "PPP IP extension", "PPP debug" or "PPPoE forwarding".

"Static IP"

"Dynamic IP"

Nothing is required for this connection type.

Save the settings when you have completed entering the data.

Setting up IPTV

Since the d link dsl 2500u modem offers only one "LAN port", you will have to choose whether to provide Internet access to a set-top box or a computer.

In the "Execution days", "Execution start time" and "Execution end time" blocks, you must specify the time interval during which the deny rule will be in effect.

Go to the next section "URL filter" and check the box "Enable / disable url filter".

You can block both individual addresses and all addresses except for allowed ones.

Select one of the options and click Edit.

The next window contains two lines:

• "URL address" - here you need to specify the address of the site that will be blocked by the router (or, conversely, added to the allowed ones - depending on your choice).
• "Port" - port 80 for the "http" protocol.

Thus, this model is not equipped with the ability to create a wireless network - this fact and rather weak technical capabilities sent the "2500U" to a well-deserved "retirement" long ago and removed this model from production.

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Repair ADSL modem DSL-2640U version C1.

Krylov P.V.

In that sample of modems,

Which I came across, about 80% of the faults were of the following kind:
Periodic blinking of all LEDs

periodic reset of ADSL connection

periodic LAN reset
The assumption that these are bad electrolytes in the modem's power supply, in principle, was confirmed. So, we open the modem. We tear off the four rubber bands from the bottom and unscrew the screws.

General view of the modem board in the following photo

The following photo shows the capacitors that you should pay special attention to. They are circled in white. These are 2 electrolytes 2200 microfarads at 25 volts and one 470 microfarads at 16 volts. They are usually swollen, the rubber bands are squeezed out.

If there is an oscilloscope, you can see the level of ripple at the output of the secondary power supply of 3.3 volts, just there is a capacitance of 470 microfarads at 16 V.

Here's a not-so-happy picture. At a voltage of 3.3 volts, the ripple is something around 0.5 volts. We change the capacitance at 470 microfarads unambiguously.

The result of the work.

Conclusions.
The equipment is not the worst, modems very rarely die from external influences, but they are not adapted for round-the-clock operation. Worked - turn off the modem, pull the adapter out of the socket, or better, pull out the ADSL line.

At home, I use ADSL home Internet via a D-Link modem. I will say that access to the Internet is not reliable. I don't know who else to blame: either the ISP; or a modem with a communication line; Or maybe the user is to blame :). Only I always noticed that the modem gets very hot during operation. Thoughts to disassemble it and somehow improve the cooling of strongly heated elements arose a long time ago, but somehow all hands did not reach. And then one day, on a spring day, I took it apart.
Turned it on, disassembled, watched about twenty minutes of online video, began to grope for hot elements. I immediately found the culprit of global warming, this is a large BGA (chip).

After her palpation, I burned my index finger quite badly. That is, in fact, the entire modem, together with the case, heats up only from it. On the reverse side, at the location of the microcircuit, I found a darkening of the printed circuit board. Although I know that the operating temperature of some radioelements is quite high, and a temperature of 70-105 ° is normal, I was sorry for the poor thing and all her surroundings, so I decided to put a radiator on it. I found a suitable radiator on an old motherboard from a computer, which was glued to the microcircuit.
Using a screwdriver, I took the radiator from the rightful owner. I decided to place it on the modem chip using hot glue. I ran around the shops, found hot glue only in a TV workshop, gave 150 rubles for it.
Hot glue in our small town is a very rare thing, so I immediately developed a fallback: we glue the radiator on superglue, applying it (in small dots) to the four corners of the microcircuit, we smear the center with KPT-8 thermal paste, sold in every computer store for 30 rubles.
Here, it is important to calculate everything correctly so that the paste spread over the microcircuit does not mix with superglue. Since the radiator did not fit completely into its intended place, it had to be cut off.
In my case, the screen of another, large microcircuit (not heated) interfered with the placement of the whole radiator, but on the exact same modem of a friend, this screen was missing, so I glued the radiator completely to it. To glue the radiator, apply a thin layer of glue to the chip, after degreasing the surface.
We press the heat sink to the microcircuit, and we drive it a little from side to side, so that the glue layer becomes more even and thinner. After thinking, I decided to glue the rest of the radiator. We glue it to the screen, and to the fins of the main radiator, aligning them. Maybe the heat transfer will be small, but it will not get worse for sure.
I was convinced of this by heating a small part of it and the screen. According to the instructions, the drying time of the glue is 24 hours, but if you do not move the radiator, then the product can be used earlier, because the glue is thick enough and does not even dry out, it holds well. We assemble the modem and know: now we are definitely not in danger of overheating. Well, of course, we note the increased speed and stability of the Internet connection at times :).

The 2500U DSL modem allows you to connect the subscriber's computer to the Internet using telephone cable lines. It finds its application where laying the most modern high-speed communications is still difficult.

Based on this 2500U router, it is impossible to organize a full-fledged local network, since DSL does not have a wireless communication module. But the principles of setting up a connection between a device and a provider company are also used in more “advanced” routers.

The D-Link network device does not support many features without which the new models are not competitive in the market.

The main ones include parameters regarding the absence of:

1. built-in WiFi module to create a local wireless network on its basis;
2. USB connectors for connecting external drives, mobile 3G / 4G wireless Internet modems;
3. ports for connecting with a cable of high-speed FTTx-optic fiber lines.

Appearance of DSL-2500U

The scope of delivery of the product purchased through the distribution network includes:

• ADSL modem;
• splitter - a device that, when connected to an input telephone line, splits the signal into a low-frequency (analog) signal for a telephone set and a high-frequency (digital) signal used in a modem;
• two cables with RJ-12 connectors, one of which connects the splitter and the phone, and the other connects the splitter output and the DSL modem input;
• patch cord with RJ-45 connectors for connecting the output of the router to the input of the network card of a computer or laptop;
• modem AC power adapter;
• instruction manuals on paper and on CD.

The following items are located on the rear panel of the 2500U router:

1. DSL connector for connecting the product to the "Modem" output of the splitter;
2. LAN connector to which network devices are connected;
3. plug connector 5V=1A for AC adapter;
4. ON / OFF button (not available on all series);
5. Reset button to reset current settings to factory defaults.

The DSL front panel is designed to inform the user about the state of the communication lines of the connected equipment and individual components of the 2500U modem. The indicators located on the front panel of the device are as follows:

• Power indicates whether the DSL modem is powered on or off.
• Status informs about the operation of the 2500U router or errors that have occurred.
• DSL shows the synchronization status of the router in the process of working with the provider.
• Internet determines the presence of a connection to the World Wide Web or the presence of critical errors in the line (red glow).
• LAN informs about the health of the communication line when devices are connected to the port.

Connecting the 2500U and Getting Ready

A telephone cable is connected to the connector of the DSL router, coming from the Modem connector of the splitter or directly from the ADSL telephone line brought into the apartment or house. The name "Asymmetric ADSL" is sometimes heard, but not entirely correct. Asymmetry is already embedded in the ADSL abbreviation in its first Latin letter (Asymmetric). The LAN connector of the 2500U modem is connected using a patch cord to the connector of the PC or laptop network card, usually built into the motherboard.

The AC adapter is connected last. The subsequent setup of the Internet connection is performed with both devices activated. The splitter does not have a separate power supply. For the 2500U router to work, it is necessary to obtain an IP address, as well as the DNS server address in automatic mode using the Internet protocol TCP/IPv4.

To configure the D-Link model 2500U modem for any provider, you need to open its interface. This is done using a PC or laptop connected to the LAN port. Enter the value 192.168.1.1 into the address bar of the web browser you are using and open on your computer. indicated in the enclosed operating instructions. Then press Enter on the keyboard. In the window that opens, you need to fill in the "Username" and "Password" fields.

By default, for most routers, these values ​​will be the login and password admin / admin. After that, you need to click "Login". Next - the transition to the main page of the interface, for different firmware versions, the software (software) has its own appearance.

The DSL-2500U router for auto-configuration requires clicking the "Connect the Internet" (Quick Setup, Wizard) tab on the main interface page. The DSL modem is configured using the Setup Wizard. It requires data received by the user from the provider. Setting up the 2500U is, in fact, semi-automatic, since at various stages of its implementation it is necessary to manually enter data from the contract. To proceed to the next step, click on the "Next" stencil.

There are many versions of the 2500U modem. From here you can see the variety of WAN interfaces. The first step is to select the connection type: PPPoE, PPPoA, IPoA, IPoE, Static IP, Dynamic IP, Bridge.

When continuing the DSL setup in sequence, you will need to additionally enter the values ​​of the VPI, VCI parameters, depending on the region of the operator providing the services.
For PPPoE, PPPoA connections, a username and password provided by the ISP are required. They remain unchanged. They are entered only when setting up the 2500U and are saved when the equipment is turned on again.

Static IP requires the entry of an Internet address (paid) assigned by the provider, which remains unchanged throughout the entire territory of the operator. Dynamic IP does not require any action on the part of the user when setting up an Internet connection.

Connecting to the Internet manually using some providers as an example

With manual configuration, it is possible to configure the 2500U modem for the user and set all the necessary parameters, without excluding those that are required without fail for the type of connection of each of the Internet operators. On the DSL modem administration page, go to the Advanced Setup tab.

"Home ru"

After entering the advanced settings of the 2500U router, click on the "Network" tab in the top row and enter its menu. Then select the WAN partition, click "Add". The operator uses PPPoE-. It must be selected from the proposed list.

In the fields "Username", "Password" and "Password Confirmation" it is necessary to write down the data received from the provider and specified in the contract. You must check the Keep Alive box.

Find out the values ​​\u200b\u200bof the VPI and VCI indicators by calling the provider. They must be entered in the appropriate fields.

This operator additionally uses binding to the MAC address of the equipment used. This address is the physical device ID assigned to it during manufacture. Before setting up the 2500U, it must be reported to the provider. The address information is located on the label of the DSL modem, located on the bottom of the case. It is a sequence of 12 digits and Latin letters and is designated MAC ID.

If there is no address on the label, the information is available in the advanced menu. To do this, in the top row of tabs, click on “Start” (Device Info). For router firmware version 1.0.50, the physical address is designated LAN MAC.

After filling in the required fields, click on "Save". The Internet indicator on the front panel of the device should light up after saving the configuration in an average of 20-30 seconds.

In the WAN tab, select the Home section, and click ADD (“Add”) in it. On the page for creating a connection, enter the VPI, VCI data from the agreement with the regional provider Rostelecom, and in the Service Category column, select UBR Without PCR from the list. To continue, click Next.

On the next configuration page, check the PPP over Ethernet checkbox and click Next.

After that, in the PPP Username and PPP Password fields, you need to enter information about the username and password from the contract. And also check the Keep-Alive item. The last action saves the connection in case of an accidental loss of communication and its subsequent restoration. Then click Next to go to a new page.

Here, check the items: Enable NAT, Enable Firewall, Enable WAN Service. In the last paragraph about service, write Rostelecom.

After clicking on Next, you will be redirected to the summary page. After checking its compliance with the previously entered values, click Finish. It is now possible to control the connection signaling on the Internet indicator on the front panel of the DSL modem.
In more detail, we analyzed the details of the settings in the article.

"Beeline"

This operator assumes that the user is using equipment that supports L2TP WAN connections. The 2500U modem in question has the following types of connections in its technical specifications:

• PPPoA.
• PPPoE.
• IPoA.
• IPOE.

The connection of the Beeline operator for the DSL router is not provided. It is supported by the manufacturer "D-Link" in models of a later release, for example, DIR-300.

NetByNet

On the main page of the interface, in its menu, the transition to the connection settings is made by selecting the WAN tab, and in it - the Home section. The connection is created by clicking on ADD. The new page allows you to select the type of connection from the contract. The 2500U modem in question is available for a PPPoE connection when receiving a network address in automatic mode and PPPoE with a static address received from the provider.

In both options, the subscriber's contract contains a username and password. They must be entered in the appropriate fields. The entered password must be confirmed in the corresponding field.

After that, you need to check the item "Clone address". In this case, the provider will see the MAC address of the computer with which the DSL modem works. Always is written in the mode selection field. In this case, the connection will be stable in case of possible failures in the communication line. The entry is completed by clicking on the Next stencil.

On the new page, you need to check the items: Enable Firewall, Enable NAT.

In the case of a PPPoE connection with a local (static) IP address, you must additionally check the Static IP box.

In this case, after clicking Next, a page will open where you need to fill in the fields with the data from the contract: the address assigned by the provider, the subnet mask, the gateway used, the preferred and alternative addresses of DNS servers.

The entered information is saved after pressing the Save Settings button. On the next page, you need to control the data of the created connection reflected on it. If their values ​​are correct, click the Finish stencil. After a while - no more than 20-30 seconds - the Internet indicator on the front panel of the 2500U router should light up, which will confirm the connection with the provider.

Bridge operation mode

With the listed providers, the DSL modem works only in router and transparent bridge modes. Repeater (repeater), amplifier, adapter or access point modes are not available to him.

If, with the settings set and saved, you need to use the 2500U modem in bridge mode, this will not cause difficulties. To do this, go to the "Configure manually" tab by clicking on it with the cursor. On the page, go to the WAN section, and in it - the Home subsection. In the created connection, adjust its type: PPPoE to Bridge, leaving the rest of the settings unchanged.

Additionally, "Encapsulation type" and service category are added. The first option is set to Bridged IP over ATM LLC SNAP and the second option is set to UBR.

At the last step, click the Finish stencil. After such a change, the DSL router only performs the function of transferring information from the telephone line to the computer and vice versa.

In bridge mode, the 2500U router works with only one computer in general. But the considered DSL model initially has only one LAN connector. The built-in firewall stops working. The computer takes over the protection against network attacks. Network Address Translation (NAT) stops working and the printer stops working.

IPTV

For the set-top box required for the operation of interactive television, it is necessary to allocate a separate LAN port. IPTV receives the stream of information directly from the provider. On other router models, the dedicated port is programmatically switched to transparent bridge mode and can no longer be used for other purposes. The 2500U modem has only one LAN port and the user has to decide on a priority connection. The question is about changing settings.

Bridge connection is required for IPTV to work. It is necessary to set the values ​​of the VPI and VCI parameters from the contract in the WAN section.

In the "Miscellaneous" section of the settings, check the "Enable IGMP" item. After that, the port is "given away" for IPTV.

Parental control

This setting is in addition to the basic functions of the 2500U. On the administration page, click on the "Configure manually" tab. In the top menu of the tabs that open, select "Control", click on it.

After clicking on "Add", it becomes possible to create a new rule. The local network for the DSL modem in question consists of only one computer, so only one rule is created.

It indicates the MAC address of the PC, prescribes an arbitrary name and puts a mark in the “Enabled” item. After that, a schedule is drawn up, which includes the days of the week, hours, minutes of the beginning and end of the opportunity to work.

In the "URL filter" section, you can block/allow the operation of sites specified by the user. Port 80 is selected. The settings are completed by clicking on "Save".

Dynamic DNS

The setting in the DSL of this parameter refers to the advanced version of the routing settings. Access is made by clicking on the "Advanced" tab. Dynamic DNS (DDNS) comes into operation in dynamic IP mode, allowing each change of address - in digital form - to leave a permanent domain name.

Security settings (antivirus, firewall) on the 2500U modem

Access to the security settings in the DSL modem is provided from the main menu when you select the "Firewall" (firewall) tab. Here you create IP filtering rules for dangerous and working addresses. To create a new rule, click on the "Add" stencil. Virtual servers and DMZ zones (virtual server dmz) are also created here. They are able to redirect all Internet traffic to a specific IP address on the local network.

Possible malfunctions and ways to eliminate them

All problems that occur during the operation of the 2500U DSL routers are divided into the following groups:

• consumer equipment software;
• hardware part of the system;
• service provider faults.

In the first case, it is necessary to separate the situations when they occur at the initial stage of configuration, and the failures that appeared during the operation of the DSL modem. At the initial stage, setting up the 2500U must be carried out with strict observance of all the requirements of the manual, the sequence of operations, saving the entered data at each stage. After finishing the DSL setup process, you need to check the received totals.

The causes of failures that occur during operation of the 2500U are often external factors: sudden power surges or thunderstorms. Great help in these cases will be the use of uninterruptible power supplies (UPS) with an autonomous battery (battery). If it is impossible to continue DSL operation, it is necessary to reset its settings to the factory values ​​using the 2500U router. And also to carry out work on the restoration of previously entered data. Firmware firmware to the latest software version will be of great help.

The indication of the DSL modem on the front panel will help in troubleshooting the hardware (“hardware”). The exception is when the Power LED is off. For this option, replacing the AC power adapter is useful. It is necessary to check the serviceability of the wires and measure the voltage with a multimeter. It will be useful to examine all cable connectors for their reliable connection and check the health of the communication lines of the system equipment. In the absence of Internet information, sometimes the PC is “guilty”. If it is possible to check this version, it can be temporarily replaced.

After the verification activities carried out, the consumer of services should call the operator's technical support service and report the problem. In the case of normal operation of the provider's equipment, the assistance of warranty or repair shops is required.

DSL Router Firmware Update

Updating the 2500U router, that is, the version of its software, is required when numerous problems accumulate. Before starting the DSL firmware, you need to carefully study the stickers on the product case, determine the version of its hardware (H / W) or the type of revision. As well as the software version (S/W) at the time of release. S/W version or line type are: annex a, annex b. And the revision is A, C, D.

On the site www.dlink.ru, you need to download the latest file with the bin extension from the Firmware folder, save it on your computer.

On the main page of the interface, go to the "System" tab. In it, select the “Software Update” item, on the new page, click the “Browse” button. After finding the downloaded file, click on the "Update" button to install the new 2500U router software. At the end of the update process, the computer will automatically restart and return to factory settings. It is necessary to re-configure the DSL router using the technology described above.

Resetting the router 2500U to factory settings

The DSL modem has a hardware and software reset. For hardware reset of the 2500U router settings to the factory values, a Reset button is recessed into a narrow slot. Its thin rod must be pressed and held for 10-15 seconds. After that, you need to wait for a minute for the blinking to stop. The factory settings will be restored.

For a soft reset in the 2500U, after entering the administration page, click on the "Configure manually" tab. On the new page, hover over the inscription "System" in the upper right corner, click it and select "Factory settings". By clicking on the item, start the process of restoring the original values, followed by an automatic reboot of the DSL router.

Conclusion

An overview of the D-Link DSL-2500U router shows that the model is used where there are only ADSL telephone lines, through which the Internet can be transmitted at a satisfactory speed. DSL is a budget entry-level device. Based on it, it is impossible to organize a local network. The principle "One modem - one computer" applies here. The history of the 2500U modem has more than 10 years. DSL has rightfully earned a "deserved retirement".

pros

The positive qualities of DSL include:

• the 2500U has a relatively easy setup process with the ability to quickly return to the original values ​​​​in case of an error;
• the possibility of using DSL in telephone lines with a high level of interference;
• the presence of a large base of components for the repair of the device.

Minuses

The negative qualities of the 2500U today are:

• lack of a wireless communication module, USB connector;
• the presence of only one network port;
• outdated element base, leading to frequent failures in operation;
• low speed of data exchange in the network.

DSL-2500U. The owner of this modem complained about the constant dumps of the Internet, if not at all connection failures. And indeed, turning on the modem, I found that the modem was not available even via Ethernet, although the lights blinked as expected.

Disassembly and repair of the D-link DSL-2500U modem

First, we determine whether the 5V power supply is to blame. We measure the voltage - deviations are allowed plus or minus 10%. If there is a suspicion of a power supply, then it and change swollen capacitors. Usually this C9, C10, sometimes C3. If the power supply is beyond suspicion, then we disassemble the router. Loosen four screws under glued legs.

Replacing capacitors in the D-link DSL-2500U modem

Under the cover of the router we see an electronic board with swollen capacitors. Capacitors usually overheat. C8 - 470uF x 16V, C14 - 100uF x 16V, C32 - 470uF x 16V, C111 - 470uF x 16V. We change them to capacitors of the same or larger capacity.

Capacitor C14 is better change to 220uF.
As a result, the repair was successfully carried out modem D-link DSL-2500U - it began to work stably. It seems that the power ripple due to the low filter capacitance overlaps the data signals and breaks the synchronization. Hence the loss of communication and unstable operation of the modem.

Other malfunctions of the D-link DSL-2500U modem

Also, sometimes, the microcircuit fails. U2 Broadcom 6301KSG. Found a solution to this problem. The source states that the chip can be replaced by AD45048.

Which in turn is quite simple replaced by assembly on your favorite KT315G and MLT-0.125 430 Ohm resistors. True, due to the spread in the current transfer coefficient, it is necessary to select resistors for a stable Internet speed. Also transistors can replace with C945, and resistors can be selected up to 20 kOhm.

Among other frequent malfunctions of D-link modems, there is often a breakdown of the external power supply. In this case, communication with the network may also be lost and the modem itself may periodically fall off. In this case, the repair will consist in replacing the filtering electrolytic capacitors in the power supply.

This completes the note about the repair of the D-link modem DSL-2500U. I hope that your modem will work stably for many years.