dslreports logo
    All Forums Hot Topics Gallery


how-to block ads

Search Topic:
share rss forum feed


Spokane, WA

Not synching at full speed

Hello, everyone. First, let me say this site is a very nice resource. Thanks to everyone who makes it possible.

Now on to my issue. I'm subscribed to 1.5 Mbit broadband service. Starting two or three months ago (not sure exactly), my modem started synching at 1024K downstream. (Incidentally, is 576 or 640 upstream normal with this?) On one occasion, I noticed it had actually synched at the full 1.5M, but that didn't last long. Here are my current stats:

DSL Negotiated Mode: T1.413
Speed (down/up): 1024 / 576 Kbps
Near End CRC Errors (I/F) : 1/0
Far End CRC Errors (I/F) : 83/0
Near End CRC(Within last 30 mins)(I/F) : 0/0
Far End CRC(Within last 30 mins)(I/F) : 0/0
Near End RS FEC (I/F) : 680/0
Far End RS FEC (I/F) : 56971/0
Near End FEC(Within last 30 mins)(I/F) : 0/0
Far End FEC(Within last 30 mins)(I/F) : 94/0
Discarded Packets(Within last 30 mins): 0
SNR Margin (Downstream/Upstream): 11/6
Attenuation (Downstream/Upstream): 63/31

This is an Actiontec M1000, BTW. More tangential questions: Does anyone know what units the attenuation is in? And what is I/F? I'm guessing it has something to do with ATM encapsulation, but I don't know anything about ATM, so...

I contacted tech support at CL, and they confirmed that the signal strength is very weak. Naturally, they say it's probably a problem in the premises, but it's not like I rewired the house recently, nor have I changed the devices that are connected or their arrangement. It's not a problem with unfiltered devices either, because everything is connected through one jack, with the other devices daisy-chained from the modem's filtered jack. Disconnecting them doesn't clear up the problem. So I'm thinking more likely it's somewhere out there on the loop. But it's only a guess, and after all, the wiring is pretty old, so I might be wrong.

And here's the real problem: as I just said, the wiring is pretty old. This house was built in 1960, and things are not easy to work with. For starters, there's no NID, just an overhead drop that disappears into the wall and terminates at a protector block in the basement. If there were a real NID, I could use its test jack. Maybe I could wire up a jack to the protector itself? Would that be advisable?

In terms of being able to isolate problems like this, the best solution would be to have an NID installed, right? But from what I've read already, they would have to ground it near the power meter or something along those lines. Is that right? Currently, the drop runs to the opposite end of the house from the power drop (makes sense, of course, since you can't risk the two cables touching), so I suppose I'd end up having to run new IW, which is not something I relish the thought of in this house.

Well, I appreciate any advice anyone can offer.


Spokane, WA
Yah, your downstream attenuation is tanking..... and the upstream SNR is not good either.

Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. The higher the number the better for this measurement. In some instances interleaving can help raise the noise margin to an acceptable level.

6dB or below is bad and will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems
20dB-28dB is excellent
29dB or above is outstanding

Line Attenuation
Measure of how much the signal has degraded between the DSLAM and the modem. This is largely a function of the distance from the exchange. The lower the dB the better for this measurement.

20dB and below is outstanding
20dB-30dB is excellent
30dB-40dB is very good
40dB-50dB is good
50dB-60dB is poor and may experience connectivity issues
60dB or above is bad and will experience connectivity issues

Call them and ask how you are supposed to test the line when you don't have a NID and see what they say. When I worked there we were required to place a NID outside when we encountered an inside protector. They still should do so nowadays, but I can't guarantee that policy still exists. And yes the ideal place for the NID is by the power ground....... but stuff happens. I would like to assume the existing protector is grounded.... AND it is best for the company when the NID is outside of a building.

NOW, you could get a surface mount jack cover with wire leads and attach that to the protector if you want. Just be sure and disconnect the inside wiring so the jack cover is just hooked to the drop.

As far as the 'I/F' thing..... I never did find out what that meant either.....

Irish Shark
Play Like A Champion Today
Las Vegas, NV
reply to ddawson
This is all I could find on the I/F thing.

"I did place the phone/DSL signal splitter directly at the Telco interface (I/F) box (so house wiring won't radiate or pick up RF near to the degree if I allowed ADSL to propagate throughout the house wiring), and the I/F box is fed via underground service from the underground right-of-way line(s) in the alley (buried electric, telco and CATV).
"You can observe a lot by watching". Yogi Berra


Spokane, WA
said by Irish Shark:

"I did place the phone/DSL signal splitter directly at the Telco interface (I/F) box (so house wiring won't radiate or pick up RF near to the degree if I allowed ADSL to propagate throughout the house wiring), and the I/F box is fed via underground service from the underground right-of-way line(s) in the alley (buried electric, telco and CATV).

I doubt that's it. The pattern in the labels suggests that "I" and "F" are separate measurements (other stats show "(upstream/downstream)" there), and each of those stats has two numbers separated by a slash. (The second, "F", number always seems to be 0, though.) Don't think they're downstream and upstream, since all of those have a "near end" and "far end" which would seem to be equivalent, and you don't report an error on your own transmission.

Oh well. It's not that important to me. Just one of those minor mysteries that is irritating to curious people like myself. I suppose only Actiontec really knows.

Boise, ID
Hi, Dawson!

Our management team would be happy to help look into this and work towards a resolution. If you wouldn't mind taking a moment to send us the account details, we'll see what's going on with your service:





Spokane, WA
Well, I did. Got a ticket number and everything. But I'm holding off until I can get around to testing at the protector. Then we'll see if it's really a problem inside or outside. Once that's determined, I'll decide how I want to proceed with CL.


Spokane, WA
reply to ddawson
Well, I finally did it. Wired up a brand new jack with about 3 feet of brand new wire to the protector, with everything else except the drop disconnected. Attenuation is still 63/31. So, I can reasonably conclude it's not IW. Good news for me, I think. Plus, I now have a test jack. Well, sort of. Still have to do wiring manually if I want to isolate the IW.

Thanks for the advice.


Spokane, WA

2 edits
reply to ddawson
Update: Called repair. Took about 20 or 30 minutes (and getting hung up on twice for some reason!). I explained the problem (again) and the testing I had done. After answering all the questions and so forth, they finally informed me that their server (do they mean the DSLAM?) had dropped my speed due to some sort of problems it detected. (Would that be because of the poor signal? Hmm? Maybe it dropped even further temporarily or something?)

Anyway, the engineers reset it, so now I'm at 1536 / 608. This is sort of good news. I'm glad to have full downstream speed back. Still the same weak signal, of course. Downstream SNR is even worse—6 or 7; I guess it would be with more bandwidth. (Part of it, no doubt, is the distance, but should the attenuation really be 63 dB?) I have to wonder, though, if this could happen again. I had no real problems for the couple of years I've been on 1.5 Mbit (other than the previous modem that was flaky and finally died when a probably already-marginal fuse feeding power for my block went bad during a thunderstorm, but that was on this end and this doesn't seem to be), so why now?

I guess unless someone here knows something, only time will tell. Working pretty well so far.


Spokane, WA
I'd be surprised if the connect speed didn't drop again....

The down and up stream attenuation should be less than 60 and the SNR should be greater than 6.

Trying to convince repair is the problem.

I spose you could try the link left in a previous message from CTL.