ADSL, known for an asymmetric digital subscriber line, is a type of broadband communication technology which is used for connecting the internet. Compared to old fashioned modem lines, the ADSL allows more data to be sent over telephone lines. It requires a special ADSL modem and subscribers must be in a close location to the provider central office to receive ADSL service.

If you are willing to get ADSL line, make sure of the major problems you may face.

The common ADSL problems and the way to identify faults along with possible solutions are listed below.

  • No Synchronisation

If your router cannot synchronise as indicated by the blinking green ADSL light, it indicates whether;

  • ADSL is no active.
  • Filters installed incorrectly.
  • The problem with the local line.
  • Dropped connections

Some of the few things with these problems and are;

  • ISP Problems: Check the ISP Service status records as they are doing any load balancing or not.
  • USB Modem: It is not an uncommon problem, but generally arises with particularly older PCs and unpowered sub-hubs.
  • Low SNR Problems: Low SNR problems generate when you are on a long line and are at a rate adaptive up to 8 Mb type connections.
  • Noise on telephone line

The cracking noises on telephone line are an indication of use of filters which are fitted wrongly and for such problem make sure of the following things.

  • If you have installed all filters in the appropriate manner or not.
  • And need to check that each of your telephone devices has connected to the filter correctly.
  • Don’t forget to filter fit for fax machines and sky boxes too.
  • Drop out of ADSL
  • If the splitter/filter connected is not in proper manner.
  • The fault on filters.
  • Some problems on the telephone line.
  • Disconnection of ADSL when your phone rings
  • Make sure of the filters condition and wiring.
  • Limits the noise on the telephone line by doing a quiet line test.
  • External factors like water and the damage on the cables disconnects the telephone line.
  • Very high amount of resistance on the telephone line cause by worn cable and damaged on joint. Make sure of the condition of the cable wire and the joints.
  • Lost your connection frequently

This type of problem is not a common but is a very rare case. However, many users do face such problem when they recently had upgraded to higher bit rate (E.g. 1Mbps to 2 Mbps) and upgrade to higher speeds. The upgrade of higher speeds results in their connections regularly drops, mainly in the time of the evening.

  • Viewing problem for some websites

This type of problem normally hampered Microsoft, eBay and Hotmail sites.

  • Set your Maximum Transmission Unit (MTU) to a lower figure.
  • Do a TRACERT (Trace Route) to make sure as if there are some problems with routing or not.
  • Absence of Dial Tone

Our Telephone lines have two cable wires: Power and Earth wire. If there are any problems with the circuit, then the dial tone do not work.

  • If there is discontinuing of the cable wires then identified by no capacitance reading.
  • Check as if all your telephones are hung up or not. Make sure the correct performance of all your cordless phones and message answering machine with AC adapters. Unplug all of them and check if dial tone has been restored or not. Check for all the outlets to make sure of the line cord secure placement.
  • Noisy Line

ADSL share line with telephones and it uses the different frequency. Two ways to reduce noise introduced by telephones are:

  • Set up the splitter at each phone to reduce noise.
  • Connect the splitter at a point where telephone line enters your house.

Other possible causes are:

  • Earth Contact: The phone line is passing through to the ground and is may caused by rubbing of the cable by the tree branch.
  • Rectified Loop
  • Battery Contact: If the phone line is in the contact with another phone line and this could results in worn isolation.
  • Attenuation

The line attenuation figure describes the range between you and the exchange of the ADSL provider. The attenuation results in slow internet speed. The line attenuation figure is expressed in dBs and you can check on your ADSL statistics of your home. As we all know the slow internet speed of our ADSL line is directly affected by line attenuation, unluckily, we can’t do anything for low attenuation figure except moving to new location.

  • The increment in line attenuation arises due to faulty in internal wiring caused by erosion on a joint.
  • If the phone line attenuation is greater than assumed, a radio frequency (RF) filter could be a better choice.
  • You must have a router which should be suitable to manage low signal to noise ratio margin figures.
  • Install better quality ADSL filter to your router and to each of your telephone device connected to the same phone line.
  • Poor and low-quality telephone cabling can introduce noise to the line. Check properly if you have a problem with in-building cabling, or just can eliminate your problem by connecting with the new modem.
  • Connect with another ADSL provider, as some of the providers are less crowded than others.
  • Universal Serial Bus (USB) Modem

USB Modems problem arises when users have the ADSL connection with their older PCs.

Firstly, check and be sure that you have recent version of drivers for USB Modem and can be downloaded from the reliable site. You should connect your modem with you PC and then install the recent version of the drivers.

The traditional/ old OS simply do not presage well with USB modems, and the solution for such case would be considered connecting via Ethernet. The common issues are that the USB modem dissipates much more power from the PC and for these cases; you are limited by the single choice of selecting Ethernet.

Since USB modems dissipate much more power from PC, it would be much preferable for such router which has power supply, router processor and its memory. The router is a main device for internet connection making your PC to get what you desire to do.

All modems require 500mA of power and modern PCs can supply full 500mA on each of USB port.

In older PCs, the power available for USB ports can create the problem if more than one USB device has to connect.

The peripherals like keyboard, mouse use limited USB bandwidth and the modem try to utilise bandwidth. So, if you want to attach other USB devices (mouse, keyboard), ensure that a USB mouse or keyboard is plugged into your PC before holding up to the modem. If not, then the router will use a fixed BW (bandwidth) and the remaining from the total BW may not be sufficient for other USB devices. For such cases like this, an error message showing that the USB controller band is exceeded is displayed.

USB modem which operates in Bulk mode could be slower speed due to the modem which unable to match the USB and DSL rate. The effects of slower speed are due to remain bandwidth which is insufficient on USB channel.

  • Ethernet/LAN connection
  • Check if both of the cables are plugged in as only one cable should be plugged. It is your choice what method of connection you like to use, but normally we suggest you to plug in Ethernet cable as the best option for you.
  • You must have to connect directly to the router. Make sure it is not connected with your ADSL network.
  • Then you have to reboot your modem and PC both.
  • Try connecting with a USB cable.

If there is no Line Sync, then this indicates that the data connection between ADSL port.

  • Make sure that there is Dial Tone on the telephone line that is using to connect to the internet via modem. If still you have the problem of the dial tone, then contact the Faults section of the telephone company that you have your telephone connected with. If there is a dial tone, follow the steps.
  • Restart your PC and Modem.
  • Check Extension leads/ Telephone Cabling.
  • Check for the DSL Filters on the telephone line and make sure that the main is phone cable is inserted as an input. The output port is 2 ports in which one port is with telephone and next port is for the modem.

  • Filtering Problem

If there is filtering problem, one of the fastest ways to find a line or filtering problem is Isolation test.

Isolation Test means:

  • Connecting the Router/modem linearly to the phone wall socket with a phone lead with not greater than three meters in length.
  • Disconnecting each and every other device which is connected to other telephone lead. This includes double adapters and extension leads.

If you have completed the above two steps, power cycles your modem. Some of the modems take some time to successful connection to the ADSL service, so please be patient and take your time. If the light goes all well and good, then move on to the one by one test. If it has not gone right within five to six minutes, follow the following two steps given as:

  • Replace the telephone lead that is connected to the modem with another lead and the dimension should not exceed more than three meters in length.
  • The above two methods help to make sure if the main problem is in the telephone lead or not. In each of the case, you must need to power cycle the modem and wait for at least five minutes to check if the ADSL light will go all fine. If it happens, you should know that you have found the reason of the defect and you must have to move on to each by one to one test. If it doesn’t, then please make contact with the technical support team for further assistance.

The one by one test should be performed after successfully managed to get your ADSL modem to connect while an isolation test is done. Simply, it is the process of connecting the devices back on to the telephone line one by one.

Make sure that the connected device has used an ADSL line filter and test the internet connection for a few good times to make sure that it continues to work correctly. If you found that it still works, connect the next device and test the internet connection.

If still your internet connection slows down or drops out after connecting a particular device, there is still a problem with the line filter or splitter.

  • ADSL LED off situation
  • Check that your telephone jack is connected to the standard telephone to check dial tone.
  • Check that the telephone cable connections are secure at the router and ADSL capable telephone jack.
  • If the router was installed but LED has not solid on, then disconnect all telephones on the line and reconnect the telephone with the use of microfilters on each of the telephone. If disconnecting the telephones turns in a green Internet LED, there may be the problem in your wiring. Make sure that you are connected to the correct telephone line and if you got more than one telephone line, be sure that you are connected to the line with ADSL service. Use a swapper if your ADSL signal is on RJ-11 jack. The ADSL+ router uses pins 2 and 3.
  • If the ADSL light was solid on, but is blinking, then switched off the modem router and wait for 1 minute. After that, switch it back on again. It will help to recover modem router. If there is still a problem, then check with ISP that the service is not being interrupted. If you recently had installed the telephone lines, you must have to connect the telephone line with DSL filter.
  • Unable to open configuration screen
  • Power down all your devices for 3o minutes and then try.
  • Disable your firewall software on PC.
  • Do not make your web browser configured to the use of the proxy server.
  • Slow speeds
  • First, shut down your computer and then unplugged the router cable from the supply.
  • And then with the start of your PC, connect the modem to turn ON.
  • When testing is peer-to-peer, make sure that all the Internet software is closed.
  • Test from a single machine with all the other computers switched off.
  • Check for the Adware/Spyware.
  • If wireless router has been used then make sure that you have enabled encryption and access control lists.
  • Test your speed using BT speed Tester.
  • If you have the number of the user accessing to the common bandwidth channel then the speed may slow down.

The DSL filters are required to separate the normal low frequencies related to voice calls from the high frequencies used by your ADSL connection. Check proper installation of these DSL filters is effective and efficient to ensure the possible performance of ADSL connection.

  • Intermittent

If your telephone line is running intermittently and drops out randomly several times in a day, it is quite difficult to find exact situation about an ADSL line. But there is a way which may help to improve the condition.

  • As you know that the modems or routers are usually left on whole day, whole month and even whole year too. So, as it is the electrical equipment and the device may need good power cycle for the better performance.
  • ADSL is very sensitive to the external environmental interference. The electric and the magnetic element around the router can cause interference which may be electrical or radio interference. So always make sure that your ADSL router is free of such electrical and magnetic elements around the router.
  • Installation Problems

The DSL modem data transfer capacity is determined by the total number of bits per bin. It is proportional to the SNR (signal to noise ratio) and the number of bins used. The protocol overhead, PPPoA connection leads the maximum link capacity for user data rate significantly on the lower level. Some of the ISPs traffic policies limit the maximum transfer rates. The wireless access makes the signal quality poor and makes the fluctuation of the actual speed.

There is the relationship between the data transfer capacity of the ADSL and the number of the channel available but the exact data capacity of ADSL per channel depends on the modulation method that we used.

ADSL are in two versions, one is CAP and another is DMT. CAP was the DE facto standard for ADSL deployments. The CAP was the old fashioned version of ADSL. The all modern installations of ADSL are based on the DMT modulation.adsl

For the DSL installation, a splitter/filter is installed and the main phone line is separated and only port is connected to the telephone and another is in modem/router.

The DSL signal can be weakened for 5 voice band devices that are connected to the line. Another major factor for the reduction of DSL signal is by the use of old telephone lines, deluge protectors and electrical impulse. The telephone extension cords elements like copper conductors are not able to maintain to reduce noise. This type of cable results in the electromagnetic interference and has more attenuation. This is only acceptable where the phone line is more than 5 KM from the DSLAM in the telephone exchange. This causes signal level to the lower value and generates local noise with attenuation of the standard signal.