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D-Link DSL Modem/Routers => DSL-520B => Topic started by: lordofpc734 on February 10, 2020, 07:52:51 AM

Title: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 07:52:51 AM
Hi so a week ago i started getting this issue. the DSL Uplink drops frequently. i disconnected the modem from the splitter and connected the modem directly to the wall. as far as i can tell, there are no issues. so today i bought a new splitter (DSL-30CF) and installed it. (phone port to landline , DSL port to DSL-520B)
the frequency of this issue has been reduced but the problem still exists. i have verified the VCI/VPI settings, (modem is in bridge mode) and MTU settings.
the cable from the dsl splitter to modem is a year old
what can i do? is this issue common with the DSL-520B?
Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 07:54:37 AM
i must add that the router is a DIR-819. but i don't think that the DSL issue is related to this router
Title: Re: DSL Uplink issues
Post by: FurryNutz on February 10, 2020, 08:04:20 AM
Do not use a splitter. Keep DSL modem connected to a dedicated phone line. Make sure the phone line signal is good up to the modem.

Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 08:21:48 AM
But i have a landline phone that i use daily. you mean i should use other phone sockets? well, they're all dead except one. (the one in use right now)
Title: Re: DSL Uplink issues
Post by: FurryNutz on February 10, 2020, 09:23:02 AM
Isn't there a extra RJ11 phone jack on the back of the DSL modem for 1 phone connection?

I recommend you have someone come in and get your phone lines and jacks in the home functional.
Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 11:23:28 AM
No. this is the backside of the modem https://images.app.goo.gl/gDKwvcKmkwp9cJtH7
also, making the other wall sockets requires demolishing, i've been using this method for almost a year. never had any uplink issues. (of course i had internet issues. but none of them were related to DSL Uplink)
what about SNR? how can i check that? and the other low level stuff.
Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 11:34:11 AM
UPDATE : i was wrong! it even drops DSL Uplink with a direct connection to the wall socket. i guess i didn't test it long enough.
so there are 3 possibilities right? A-faulty cable between socket and modem, or faulty socket. B-Modem hardware issue. C-ISP issue.
Title: Re: DSL Uplink issues
Post by: FurryNutz on February 10, 2020, 11:34:42 AM
Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 11:39:20 AM
Right, now what i am asking from this great forum is who owns a DSL-520B? did they have any issues (like DSL uplink etc...) with it? is this modem known for DSL uplink issues?
Title: Re: DSL Uplink issues
Post by: FurryNutz on February 10, 2020, 12:27:02 PM
Been a while since anyone has posted about this modem. Look back at historical post, haven't seen anyone posting about the UPLINK having problems.

I would ensure the phone line and signal up to the modem is good. Contact the ISP and maybe have them send a tech. You might need the phone services tech to help out with cabling and ensuring the phone system and signal is good as well.
Title: Re: DSL Uplink issues
Post by: lordofpc734 on February 10, 2020, 01:00:26 PM
alright. thanks
Title: Re: DSL Uplink issues
Post by: LarryNOTtheCableGuy on April 20, 2020, 12:08:27 PM
Hi so a week ago i started getting this issue.
I've had DSL-520B ADSL modems installed in two different locations for several years. Considering your internet connection was working fine before the trouble started, here are several things you should check, in the order of likely cause:

1.  Using a multi-meter, check the voltage output of the power supply. Based on my personal experience, these things have an unnaturally high failure rate. The output should be dead-on 12V and not fluctuating.  I've had cases where the output voltage has dropped to 9 or 10V, or started to fluctuate between 10 and 12V, and in both cases the modem continued to operate correctly for short periods of time. The power supplies have been a problem for some time now, and for a while you couldn't even get OEM replacements from D-Link. Then the modems became scarce as well, to the point where it looked like D-Link was preparing to discontinue them. Last Fall a new supply appeared on the market, and I've since purchased three. The new ones are Hardware Version T2, and come with a new style power supply. If you find that the power supply has failed, you can purchase a universal power with the correct voltage and polarity (e.g., from Amazon). I've done this at one location with one which has a secondary 5V USB output, which is used to power a Raspberry Pi running PiHole. Your other option is to simply buy another DSL-520L modem (see below).

2.  The next likely cause of your problem is that the modem itself has started to fail. I've had three modems fail in the past two years. My impression is that they only last four or five years. The usual symptoms have been precisely what you're seeing; they work fine until they don't - reset and repeat. I haven't found any way to determine if a modem has failed, other than to swap it out for a known good one. So once again, I suggest you buy a another DSL-520L modem. In addition to giving you a known working modem for the purposes of troubleshooting, it will act as a spare. If you're planning to have DSL for the foreseeable future, trust me, you'll need a spare. I now keep configured spare modems and routers at both locations.

3.  Try to determine if your phone line has become noisy. This can either be due to a changes inside or outside your home. Disconnect EVERYTHING from your phone line except for one phone. Have a good listen; if you hear ANY crackling over the dial tone, that's a problem. Service providers have specially maintained "silent" lines that their repair staff can call to check the quality of a line. These numbers are not published, but you might be able to fine one listed on the internet. There's lots of good information on the internet for troubleshooting phone lines. If you've made ANY changes in your home (i.e., repairs or renovations), double check that they haven't affected your phone line. Only after you're convinced that the problem is due to line quality, and that it's OUTSIDE your home, should you call your service provider.

4.  Does the problem only occur at a particular time of day? Cheap dimmers and timers can transmit noise over your home's electrical system, which WILL affect your DSL connection. At my summer residence I have a pair of carriage lights installed on the outside of the garage. These lights have a built-in dimmer/timer which allow the lights to come on automatically at dusk, and stay on for a number of hours. They also dim after a few minutes, if they don't sense motion. Initially I had "good old fashion" incandescent bulbs installed in these lights. Shortly after replacing these with "cheap" LED bulbs I started to have problems with my DSL connection. I was finding that my previously good DSL connection (no problem streaming video) was slowing in the evening (continuous buffering while streaming video). Initially I thought that my service provider had finally over sold the service in the area (small village of 400 families using 256 DSL connects). It took me nearly 3 months to realize it was the damn carriage lights, and only after I'd read a story on the internet about someone's DSL connection being affected by the dimmer on their neighbours porch lights. As soon as I swapped back the incandescent bulbs, the problem disappeared. I now have top quality dimmable LED  bulbs installed in these lights. So, have you recently installed any new dimmers, timers or other electrical equipment or appliances which could be creating noise on your home's electrical system?

If you've exhausted all of the above possibilities, call your DSL provider and have them check out your service. At this point it's likely that the problem is at their end.

Hope this helps,

Larry ....
Title: Re: DSL Uplink issues
Post by: lordofpc734 on April 26, 2020, 01:54:25 PM
Whoa! thanks for the reply!
a few things to answer, the one i got is hardware revision T2 and the store i bought it from had a 3 year warranty on it (Not by D-Link)
4 weeks ago, i called my ISP and they said everything on their part is oK, but they will send an inspector to come and check my cables (i live in a flat, the inspector did something with the phone box i think) that didnt do anything. i inspected my SNR Margins and found out that they;re low. 6.0 / 5.9.
Also, phone line has some noise in it but i think thats because of the crap speaker of the landline phone. also, This is the fun part: i discovered that picking up the phone or calling someone would trigger a disconnect. so i said :freak it and i tried it out with my Old splitter, instead of the new one. and that got fixed
3 weeks ago i had online classes and such therefore frequent disconnects were not acceptable. so i ran the modem in G.DMT mode. that dropped the speeds from 15 to 9. but i had no drops. 0. none. and my snr margin upload increased from 5.9/6.0 to 8.0
the surprising part is this : my neighbor. we live on the same floor and my unit is right next to him. he also uses a Dlink device ( a DSL combo unit) his upload SNR is 28!!! we dont use the same ISPs but im pretty sure our phone lines go thru 1 phonebox and at least 1 same DSLAM.
a few days ago i decided to try and see if running in safe mode for 3 weeks somehow fixed it, my SNRs were the same (6/6) but since 2 days ago, i had no disconnects even when actively using the phone. (also i did try a direct connections waaay before all of these)
so idk, maybe my issue is gone, maybe its not. i dont have a multimeter to see if t=its giving 12VDC to the unit so idk about that,
about the dimmer/light thing, we dont have any dimmers. we only have simple switches. also, i must mention that this setup was fine for almost 6-7 years (the DSL520B is new. i am talking about the days of my old combo unit)
for now, i just have to observe, if it still drops then honestly, i will Switch to VDSL and get a new modem. that should also provoke my ISP to inspect my internal lines too.