Sonic.net

Hi Sonic, I have a noisy line from the street to my modem. The cable is standard unshielded 4 pair telephone cable. Do you know of any industry line filters that might clean up the noise? Not the filters so a phone can coexist, I mean a real noise filter. When I hook up the modem in my condo phone closet I get 19-20Mbps down.. Any suggestions appreciated! Here are my stats:

SNR Margin
:
8.4 9.7 db (Down/Up)

Line Attenuation
:
21.6 10.1 db

Data Rate
:
11688 1115 kbps

Max Rate
:
12468 1124 kbps

POWER
:
0.0 11.3 dbm

CRC
:
13 65391

Talk to your HOA to see if they would allow you to install a homerun using twisted pair. Although I'm not familiar with the types of filters you're referring to, I would think they may attenuate the full spectrum or not enough spectrum.

The last time I worked on a friends home phone wiring I found that whoever installed it had gotten really "creative" with how he attached the wires at the NID and phone outlets:

The cable was 4-pair twisted pair cable (so far so good) using the standard TIA/EIA 568 wire colors. The NID had the usual red and green screw terminals while the old outlets had R,G,Y and B (for red, green, yellow, black) next to the screw terminals.

To my horror whoever installed the cable took the solid Orange wire and the solid Green wire from pairs 2 and 3 and used those for the line that he was installing. Needless to say this completely defeats the purpose of twisted pair wiring and DSL performance was just plain awful.

When I pointed out to a neighbor in the same building that their unit had been wired in the same wrong way I was told that they had given up on DSL and switched to cable for phone and Internet instead.

While I hope that this isn't common practice everywhere, it may still be worthwhile to check that the two wires for your DSL line are really wires from the same pair in the cable.

leibold wrote:To my horror whoever installed the cable took the solid Orange wire and the solid Green wire from pairs 2 and 3 and used those for the line that he was installing.

Leibold, don't you ever play pool? Solids trump stripes, right?

klui wrote:Talk to your HOA to see if they would allow you to install a homerun using twisted pair. Although I'm not familiar with the types of filters you're referring to, I would think they may attenuate the full spectrum or not enough spectrum.

I'm actually on the HOA board. : ) A home run will be difficult. I've tried two different pairs in the cable and tied all the other pairs together and grounded as a "shield." The building is a live/work and some creative liberties have been taken with the phone wiring. I do have coaxial running from the phone closet to my unit. Maybe I could use a ethernet coaxial bridge- although they are pricey.

Any "noise" filters you attempt to use will attenuate the same frequencies that your dsl is using, so by reducing the noise, you would also reduce your dsl signal. If the condo wiring does not meet CAT3 specs, you will not have much of a chance to get above the 12 meg range. I fear that new wire to your condo is about your only hope. If you have access to a power outlet in the phone closet, you could move your modem there and add a wireless router and hope for good wireless signal to your condo. Of course anyone with access to the closet can disconnect your dsl modem.

Or, again, if you have power in the wiring closet, put just the DSL modem itself in the closet, then use a pair of these to connect the modem output to the coax run to your unit:

http://www.amazon.com/Dualcomm-Ethernet ... et+to+coax

Edit to add: I'd first try it without the DSL filter output connected to the phone pair to ensure it'll work, then add the phone pair to the output of the DSL filter to see if the noise coming back from your unit will couple to the DSL modem. If it does, then you'll need a noise filter after the DSL filter to feed the phone pair to get rid of that noise.

Robin wrote:I do have coaxial running from the phone closet to my unit. Maybe I could use a ethernet coaxial bridge- although they are pricey.

If the coax isn't tied down I'd seriously consider using it as a fish wire.

It is not possible to filter in band noise.
You can try the coax with baluns at both ends, not any converters.
Best bet is to put the modem in the closet inside a locked box.
Use the existing pairs for ethernet. Possibly POE to power the modem.

The baluns and POE are great ideas. I will try it and report back in a month or so.

designnet wrote:It is not possible to filter in band noise.
You can try the coax with baluns at both ends, not any converters.
Best bet is to put the modem in the closet inside a locked box.
Use the existing pairs for ethernet. Possibly POE to power the modem.