The whole line speed issue...

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bazzer

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#106214 23-Jan-2008 00:27

Really? I thought only the POTS devices needed filters? Can't the modem connect direct to the line?

Niel

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#106219 23-Jan-2008 05:08

Yes, remove the filter from the modem. It is only phones (and alarms and other non-ADSL devices) that need a filter, and the modem will work poorly if filtered. And no, a modem will not drop the line from an incoming call (if all other devices are filtered).

The purpose of the filter is to remove ADSL signals from the connection to the phone and to stop the phone from interfering with the ADSL signals, that is all. Phones were designed before ADSL and thus can not handle ADSL signals, that is the only reason why you need filters. If a modem drops the line from an incoming call, then it is probably the phone that is placed right next to the modem causing electromagnetic interference which is fixed by moving the phone away. Or the "hook" switch in the phone is putting noise on the line when you lift the hand set and interferes with the ADSL signals which is fixed by fitting a filter which blocks noise from the phone from going out on the line.

The filters which has a modem socket on it has a straight through connection to the modem socket, those things are simply to make it convenient for you to connect a modem and a phone to one socket without having to also add a multi adapter. But it is one more thing between the modem and the line, and the more connection there are the more chance of something going wrong. Especially on something that costs about 50c to make and is mass manufactured.

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pm

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#106307 23-Jan-2008 15:37

inquisitor: @pm
Yes, test it without filter. That will work as long as nobody calls you on your landline. An incoming call will usually interrupt the ADSL connection.

Ok here's the results:

Router Status Page:

DOWNSTREAM:
SNR Margin: 12dB
Line Attenuation: 48
Data Rate: 4326

UPSTREAM:
SNR Margin: 32
Line Attenuation: 30
Data Rate: 165

So SNR down has increased and data rate increased by .326.

Niel

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#106359 23-Jan-2008 20:19

According to http://www.telecom.co.nz/binarys/adslplus_07_dec_2007.pdf the Howick exchange is indeed huge, second only to Auckland Central. You are scheduled for upgrade to ADSL2+ now. During the switchover period you will find random disconnections until the end of the upgrade phase when Telecom will fine tune the lines and things will settle.

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pm

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#106361 23-Jan-2008 20:30

Out of curiosity, how are the exchanges connected to the central station? Through copper or optical fibers? If its copper then I can understand why full exchanges = slower speeds, but if they're optical fibers I find it hard to believe that bandwidth is an issue.

Also, if Auckland central has the biggest exchange does that mean they have the slowest speeds in auckland? I guess i'm trying to see whether or not people know what they're talking about when they say "full exchange" like every ISP does...

But Neil, thanks for that update with the whole ADSL2+. Lets hope for some difference!

cokemaster

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#106367 23-Jan-2008 20:40

pm:
Out of curiosity, how are the exchanges connected to the central station? Through copper or optical fibers? If its copper then I can understand why full exchanges = slower speeds, but if they're optical fibers I find it hard to believe that bandwidth is an issue.

Most exchanges would use some form of fiber. The speeds can vary on a lot of conditions.

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inquisitor

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#106448 24-Jan-2008 04:15

The fact an exchange has a optical backhaul connection doesn't necessarily mean there's unlimited bandwidth available to the customers served by the exchange.
Beyond the fibre cable itself you need pricy hardware (generally an DSL-AC = Access Concentrator) in the exchange, which handles all the traffic between the DSLAM (that's where the copper wires from your house are connected to) with the backbone.
Further you must keep in mind that except for the company owning the fibre cable (Telecom), all the competitors have to rent capacity from the owning company, who usually doesn't let the physical fibre itself, but only bandwidth on it. So bandwidth upgrades on the backhaul occassions costs, too.

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pm

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#106553 24-Jan-2008 16:49

Oh I see...

zeltacore

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#107051 27-Jan-2008 17:12

I'm having problems with the attenuation and filtering.

I read the previous posts about connecting your modem/router straight to the phonejack, which I did, bit I noticed the attenuation and speed (connection rate) change quite a bit.

Modulation: G.dmt.bis

Previously it was around 46dBs, now it's 52

Connection rate: 1050kbps before, now is only 756kbps...

However, I noticed that the upload rate has increased from previously 96kbps to now 162kbps...

EDIT: I just realised that whenever I'm connected with adsl_2plus, my attenuation is much higher and data rate is much slower, the problem is that when I reset the connection, most of the time it uses G.dmt.bis, and occasionally it goes into 2plus.

I saw a few others who posted have similar attenuation as me, around 46-48, but why is my data rate so low... my SNR margin is around 10-12 as well.

I'm on xtra, go large, I know it's a dodgy plan, but all the people I know and asked (who also uses go large) gets at least around 2500kbps (connection rate).
I'm around 3-3.5Km from the exchange, all jacks are filtered. I do have an alarm system, but it's not connected to the company anymore. D-link 504T router and no extension cable, using ethernet. I think I'm with the Hamilton East exchange (live in Hillcrest)

I thought the adsl2+ would boost the speed, but not really, the attenuation dropped 1 or 2dBs, SNR margin increased 1 or 2, data rate increased about 100-200kbps. From when I first started, which was 500-700kbps (rediculous). However, as mentioned before this new speed and such are only obtainable if I'm connected with the G.dmt.bis modulation...

It's been like this since the beginning. Slow data rates.

Any help would be appreciated.

zeltacore

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#107202 28-Jan-2008 16:03

Can someone please help?

Thanks

cyril7

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#107203 28-Jan-2008 16:03

46dB on ADSL1 would indicated around 3.3km of line, which ties up with your estimation. The S/N is a bit low which may be causing low rates, with 46dB and 13-15dB S/N you should get around 5Mb/s download. What we also dont know is what the BIN patterns or frequency response of the line is. It could be that there is a stub on your line due to a incorrrect patch or maybe some bad joints. It could also be a problem of a bad line card in the DSLAM.

First off I would want to be capturing the line directly after the demarc and before the security panel, just because you have ended your security monitoring contract does not mean that the line does not still go through the panel. If you can connect your modem directly to the inbound line without the security panel and any other internal wiring connected it would be useful. If the connection is still poor then you will need to get telecom involved.

ADSL2+ does not perform that much better than ADSL1 on lines longer than 2-2.5km.

Cyril

zeltacore

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#107205 28-Jan-2008 16:14

Thanks Cyril,

I will look into the security issue, problem is whenever I open it, the alarm goes off... Might need to contact the company. So IF there is something wrong with the line card, will that affect everyone using the exchange? I also have this unknown device which was connected to the phone line somehow, which rings, if all the phones are unconnected from the line, I took out a few wires on it (now it doesn't ring anymore; do you have any idea what it is?

Many thanks.

cyril7

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#107207 28-Jan-2008 16:21

Line cards normally come in 8 or 24lines per card, so only that number of subscribers may have a issue, it could also be just a single port of a card is effected, but I think I would first make an effort to isolate the line to as close to the demarc as possible before pointing a finger at the line card which you have no immediate control over.

You should be able to open the security panel if the alarm is disarmed. If its still armed or at least to a level to trap out the tamper switch on the box and you dont know the code then and dont intend to use the service/security system then open the box, pull the power off (there should be a power switch or fuse inside the alarm panel, and then pull the battery terminal off the alarm is now dead and the noise should stop.

The Bell device was most likely a extention bell, this most definitely should not be across the line without a filter, so removing it totally is recommended.

Cyril

zeltacore

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#107210 28-Jan-2008 16:31

Thanks for the insight! I will give it a go.

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