Adsl Led Turns Off At Random - Need Power Off/on To Establish Connection

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knura

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My problem is different from that described under another topic Modem Adsl Light Not At All Blinking

I have a D-Link 502T modem. This is my second modem from MTNL and in service for 14 months - the first one RIP'd in 2 months.

For the past couple of months, the ADSL LED goes OFF randomly - there is no pattern. Sometimes this does not happen for days and sometimes it happens 2-3 times in a day. All other LEDs are BLINKING. I can ping the modem on it's LAN port 192.168.1.1 and access it via HTTP and TELNET but no traffic to the 'Net.

Soft reboot (thru telnet session) does not fix the problem. To restore the ADSL connection I have to power cycle the modem.

The problem could either be in the DSLAM card @ the local exchange or in my modem. I have lodged a complaint with MTNL but no response so far. The problem is that once the modem is power cycled, the DSL connection comes back into service. The guys @ MTNL will claim nothing is wrong with the modem.

Anyone else experienced this? What did you do to solve the problem.
 
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ogtripleog

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i think that this is most probably a problem with ur line.. login to ur router and check the line stats such as snr ratio and attenuation.. some modems will lose sync if the snr is too low. also some D-Link modems have had problems with this and u might try updating the firmware
 
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knura

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Good points ... The firmware is latest (May/2005). When the modem is sync'd to the ADSL line the parameters are as follows:

Max Tx Power -38 dBm/Hz

Item Downstream Upstream Unit
SNR Margin 31 25 dB
Line Attenuation 18 9 dB
Data Rate 256 256 kbps

I am located ~2 Kms. from the local exchange. It would be interesting to see how other users
fare with the above params.

QUOTE(cyberwiz @ Nov 10 2006, 02:31 PM) [snapback]68364[/snapback]
is ur router connected to a UPS?
[/b]

Yes, I have a UPS supplying power to my router, 2 ethernet switches via a power strip. What is the significance of the UPS?
 
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ogtripleog

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sorry man all i can say is try some other modem on the same line and if it is resolved then it's the modem.. unless someone else can think of a better idea :unsure:
 
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cyberwiz

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Ur line stats are normal,therefore i feel that my hunch is correct. I think ur problem is related to the power fluctuation. Actually there is a flaw in DSL 502T, ie. whenever there is a power failure/fluctuation the DSL 502T will lose the ADSL link inspite of being connected to the UPS and will never recover. During this time the other lights remain normal and the modem remains pingable and also responds on port 80 ie web interface...
 


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ogtripleog

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yea but wasn't this fixable by firmware? are u sure u have the latest firmware? :unsure:
 
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knura

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QUOTE(cyberwiz @ Nov 10 2006, 08:55 PM) [snapback]68397[/snapback]
Ur line stats are normal,therefore i feel that my hunch is correct. I think ur problem is related to the power fluctuation. ... snip ...
[/b]

Shouldn't more subscribers with the D-Link 502t be experiencing this sympton if the power fluctuation (given that is fairly common) is causing the modem to loose sync on the ADSL port?

By chance, I also came across the local phone linesman tinkering @ the neighborhood jn. box earlier today. When I described my problem he said the something similar about the modem's power brick; that the power brick was the culprit. Since my modem is rented, he said MTNL would replace it. Apparently, it is a known problem to MTNL yet my complaint @ the local exchange has not been looked at.

I'll take this modem to MTNL next week and hopefully, the replacement will work properly.

Thanks to all who participated :)

This is what I have - Firmware Version : V2.00B01T01.ML.20050530. Just checked DLink's site - this is the latest version.
 
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cyberwiz

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QUOTE(knura @ Nov 10 2006, 09:48 PM) [snapback]68401[/snapback]
Shouldn't more subscribers with the D-Link 502t be experiencing this sympton if the power fluctuation (given that is fairly common) is causing the modem to loose sync on the ADSL port?
[/b]

Its an established problem already..i dont know why more ppl are not reporting..maybe they are not observant enough and attribute the problem to other things rather than the real culprit.

By chance, I also came across the local phone linesman tinkering @ the neighborhood jn. box earlier today. When I described my problem he said the something similar about the modem's power brick; that the power brick was the culprit. Since my modem is rented, he said MTNL would replace it. Apparently, it is a known problem to MTNL yet my complaint @ the local exchange has not been looked at.
[/b]

I doubt if even MTNL understands the problem..let alone a linesman..even dlink had a hard time figuring it out when i reported it to them..they couldnt come up with any soln and i had to ultimately change the modem
 
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chicmagnet

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well yeah i have this problem too.. but hmm. its rare ..so i dont bother...
 
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knura

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It is annoying when it has happens during the early part of NU hours e.g. around 01:00 thereby screwing up the download session for the rest of the night..
 
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randomboy

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dear knura,
This problem is not uncommon one. See my thread https://broadbandforum.co/Frequent-Disconne...ions-t7780.html
Unfortunately I have not yet seen anyone really tackle this headon. The main reason I think is bcoz we are expecting mtnl lines to konk off and do not really feel that fluctuation could be a cause. Well best of luck in finding the answer and if you do please please let me know too bcoz I am pretty exhausted by now trying to find an ans. to this.( I have a switch in between the router power supply and the UPS so that I can shut it off and start it as soon as something off this sort occurs)
 
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baudhayan

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I have heard lot of clicking snd from my UPS indicating power fluctuation (which happens a lot in my bldg). But thank god I don't hv this ADSL problem. Anyways nowadays u do get an ADSL PCI Card to plugin to the PC. Why not install this card & get rid of power fluctuations since the SMPS gives a perfect power o/p.
 
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knura

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Power fluctuation is an endemic problem all over India. For this reason, I use UPS to power my network devices and PCs. My problem has manifested since the monsoons in Mumbai. The engineers at the exchange have done line testing and found an earthing fault. They plan to move my service to another circuit and then wait/observe to see if the the problem still occurs. If it occurs then they will consider replacing the modem.I have a LAN with a few PCs/Notebooks on it. They all use the router as the gateway. If I use a PCI card then I need to have that particular PC remain ON so that other computers to access the `Net. The power usage of the router is much less than that of a PC.
 
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knura

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An update: Fault with the line, fixed and DSL502T replaced. These two seems to have solved the problem. Seeking the local linesman's help is more effective than writing complaints to the babus. My linesman asked me to visit the local exchange and talk to the engineer. My line was tested and they found an earthing problem with the line. The engineer explained that until the 'earthing' problem was rectified he was hesitant to replace the DSL502T modem. The helpful linesman moved my tel. service to another pair that solved the 'earthing' problem. However, the modem ADSL light still went OFF and stayed OFF until the unit was power cycled. I took the modem to the engineer @ the exchange and he replaced the modem. For the past 2 days things have been working OK. If the problem manifests again, then I'll replace the splitter.