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I have made a contract recently, for a DSL only line (dry DSL; no telephone) at 10Mbps. From the day one it is disconnecting every now and then. After complaining to the company they tried to make the line stable first by lowering the speed to 2Mbps and increasing finally to 7Mbps. At 7Mbps now it is stable.

My contract is for 10Mbps and I want that speed. And because with 7Mbps the upstream goes quite low. Now the company technician is telling me that this is the limitation at my end and I must do what he is suggesting to get what I want.

Some of the stats I have copied from the ADSL router at 192.168.1.1:

  • Line standard: ADSL2+
  • Channel type: Interleaved
  • Downstream line rate (kbit/s): 7111
  • Upstream line rate (kbit/s): 56
  • Downstream SNR (dB): 19.6
  • Upstream SNR (dB): 12
  • Downstream line attenuation (dB): 22
  • Upstream line attenuation (dB): 16.9
  • Downstream output power (dBmV): 0
  • Upstream output power (dBmV): 10.9
  • Downstream CRC: 200
  • Upstream CRC: 0
  • Downstream FEC: 46651
  • Upstream FEC: 6909

I have seen this question and answer thread about the right gauge of wire for an ADSL line, but still I need an answer. My question is:

Should I really spend money purchasing Cat 6 instead of using the in-building pre-installed normal telephone line wire?

Will it really improve things?

I am on the 3rd floor, so will it work at a length longer than 50 feet?

If yes will I be using only two lines—one pair out of four—from that Cat 6 cable?

Also can someone suggest what’s going wrong here—if anything—and what would be the fix?

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tod
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  • Could you please add some details regarding your situation? Why is the technician suggesting the upgrade? The DSL is not working at all? The speed is poor? What is the distance between your house and the DSLAM? – Pincopallino Mar 07 '15 at 15:02
  • you don't define `normal telephone wire`, but over the years it's changed a bit. 50 years ago telephone wire wasn't even twisted pairs, it was 4 straight wires in a jacket called quad cable. – Tyson Mar 07 '15 at 15:02
  • My telephone wire is still just 2 wires, untwisted. (It is about ½ an inch thick, though - probably survived the war;) – Tetsujin Mar 07 '15 at 15:05
  • @DanielB - me? or tod? I have no trouble getting my advertised 150Mb… though that comes over glass, not copper ;) The copper was actually good to 8Mb, though, back when that was the max available. – Tetsujin Mar 07 '15 at 15:14
  • @tod I actually had my old ADSL router installed on the ground floor, as close to the supply as possible & pulled CAT5e through the rest of the building before hitting my network, max 30m lengths. It is still in use today, with uprated internal networking & is good to gigabit over those distances, but I'll have to upgrade to CAT6 it if/when we go to next gen speeds. – Tetsujin Mar 07 '15 at 15:17
  • @Tetsujin That was addressed at the OP, of course. I easily got up to 50/10 MBit/s over copper using VDSL2, even though the cabling in that house was positively ancient. – Daniel B Mar 07 '15 at 15:30
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    I think what the tech was possibly getting at was something similar to my setup - get off the POTS as early as possible & run actual Ethernet from a modem/router located near where the POTS enters the building. – Tetsujin Mar 07 '15 at 15:37
  • I have added the details. Pardon me all for just not mentioning them before.. I was actually mentally messed up bcz of my problem. Thanks all for comments. I would appreciate any further... – tod Mar 07 '15 at 18:29
  • As an aside, if you do install new network cabling, I find Cat6 to be very annoying to work with and not worth the added trouble and expense unless you're planning to do 10GbE in the future. I don't think using Cat5e will improve your DSL speeds. If it will, there's some other problem involved like a nearby EMI source or an unfiltered phone (even if you're DSL-only, things might still be plugged in somewhere) that's causing the problem. – Jody Bruchon Mar 07 '15 at 18:31
  • @JodyLeeBruchon So, there isn't any need to go for replacing that telephone line with an Ethernet cable, right? No, I believe things are not plugged in at somewhere. – tod Mar 07 '15 at 18:36
  • I can't see how it would help. Cat5e is designed to minimize *crosstalk* between pairs. DSL is carried over a single pair; unless you're using another pair in the same cable for data transmission, there's no crosstalk to prevent. EMI sources such as fluorescent ballasts and old copiers will get on the wires regardless because they're unshielded. – Jody Bruchon Mar 08 '15 at 02:51

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If the building's wiring is truly the culprit, which can be determined by the technician wiring a jack as close as possible to the demarcation point, and to that, temporarily connecting the DSL modem, so an improved SNR can be demonstrated, then indeed, a new line is indicated to bring the desired service to your apartment.

A reference to DSL statistics can be found here, at DSLReports.com

Nevin Williams
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  • The category of wire has only a negligible effect on the cost. Most likely, the problem is that the existing wire is untwisted, has splices, and/or connects to fixtures with very high capacitance. The most common place for the problem, in my experience, is the panel closest to the demarc. Second most common is jacks and T's in the run from the panel to the jack the modem is plugged into. – David Schwartz Mar 07 '15 at 23:53
  • Yeah, I checked some prices on Amazon after posting, and didn't see much of a difference. There can certainly be quite the rat's nest (even literally) in building walls. – Nevin Williams Mar 08 '15 at 02:53
  • @NevinWilliams Thanks, I will try your suggestion to see if the building wiring is truly the culprit. – tod Mar 08 '15 at 07:15
  • Yes, It was the problem. – tod Mar 09 '15 at 20:42
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I have added some details to @Nevin Williams' answer. In fact his answer led to the solution. But, what were the outcomes, I also wanted to share those.

Here the building wiring was creating the problem and it was solved by using external CAT-6 FTP wiring.

The exact answers to the questions asked go as following:

Should I really spend money purchasing Cat 6 instead of using the in-building pre-installed normal telephone line wire?

Ans: Yes if the test shows a difference, as said above.

Will it really improve things?

Ans: Yes it will surely improve.

I am on the 3rd floor, so will it work at a length longer than 50 feet?

Ans: It (CAT 6 FTP) has already worked perfectly for a length of 51 meters (~167 feet) to carry a DSL line.

If yes will I be using only two lines—one pair out of four—from that Cat 6 cable?

Ans: Yes, only one pair.

Also can someone suggest what’s going wrong here—if anything—and what would be the fix?

Ans: well, After the change of this cable the stats in question have been changed to the following(which show an improvement and a stable connection, as we can see here about SNR and attenuation):

Line standard: ADSL2+
Channel type: Interleaved
Downstream line rate (kbit/s): 10239
Upstream line rate (kbit/s): 510
Downstream SNR (dB): 19.8
Upstream SNR (dB): 29.8
Downstream line attenuation (dB): 12.5
Upstream line attenuation (dB): 5.5
Downstream output power (dBmV): 0
Upstream output power (dBmV): 12.6
Downstream CRC: 0
Upstream CRC: 0
Downstream FEC: 11
Upstream FEC: 0

Also as an important note I would like to mention that, I did get 10 Mbps sometimes with internal wiring, but it used to decrease Downstream/Upstream SNR to ~6dB, while its now ~20dB and ~30dB, respectively. That's the big gain, that really solved the problem of disconnection.

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