Any Ideas on Where My Low Synch Speed Comes From?

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pcrosley

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#23456 30-Jun-2008 09:40

Hi,

I've been trying to resolve my lousy synch speed (data rate) for a long time and I cannot seem to come to any better situation.

I am on the GDW2 (Glendowie) exchange about 2 km away (according to Telecom). I am on the Xtra Pro Advanced Usage plan (FS/FS). I have a 3Com Wireless 11g OfficeConnect Modem/Router [3CRWDR100A-72] with the latest available firmware [2.06T13 (Apr 25 2007 17:06:30)].

[BTW, anyone know for sure where the GDW2 exchange is?]

I have moved my modem all over the apartment to see if I can locate the first outlet, with everything else unplugged, but there is no significant difference in speed. All my other appliances are filtered.

Here are my current stats:

Upstream:
    Data Rate - 914 Kbps
    Noise Margin - 11 dB
     Attenuation - 27 dB

Downstream:
     Data Rate - 1008 Kbps
    Noise Margin - 12 dB
     Attenuation - 26 dB

Clearly I should be getting more speed than this!

Is it the modem?

Does anybody have any experience switching FROM a 3Com to something else?

Any advice would be most welcome!

cyril7

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#141393 30-Jun-2008 10:12

Clearly not right, 26dB agrees with your 2km line length, 12dB Noise Margin should be fine, not great but not cause issues, on that line you should readily be able to achieve 6-7Mb/s. I assume your stated up/down rates are taken from the router status not from speedtests. I suggest you talk to Xtra and ask if they can reset your port and see if it helps, it could be that your ADSL1 modem is not negotiating a good speed with the newer ADSL2+ ISAM, not that it should be an issue, but purhaps they can do something from there end.

Edit: Just one point, how many phone points do you have, it could be issues with a complex star wiring setup that often happens, and filters on each phone device does not help. This could cause sections of the DSL band to be unusable yet still give good attenuation and noise results. The fix for that is to fit a central filter. To test if that would help you would need to find the first phone point, and isolate all wiring from there and connect your modem there to check. Also do you have a back to base alarm.

Cyril

xpd

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#141415 30-Jun-2008 11:05

Ive got the same router. It is ADSL2+ compatible

Im exactly 2km (as the cable lies) from my local exchange, and get the following :

Data Rate
Stream Type     Actual Data Rate
Up Stream     160 (Kbps.)
Down Stream     6592 (Kbps.)
Operation Data
Operation Data     Upstream     Downstream
Noise Margin     26 dB     12 dB
Attenuation     42 dB     38 dB

However Im not on a DSL2+ plan etc and I think my port is set to ADSL1 to help with some faults I was having a little while back.

Could be dodgy port at the exchange.... that found mine was faulty 2x and then the wiring at the excahnge was faulty. Fixed all that and ive been on 6mbps+ ever since.

Gavin / xpd / FastRaccoon / Geek of Coastguard New Zealand

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pcrosley

49 posts

Geek

#141605 30-Jun-2008 17:55

Thanks Cyril and Xpd

Called Telecom who duly noted my complaint, looked at my records and then said my speed "appears to be a bit slow, but is actually normal"!

After more discussion they had me reset my modem again and it came up synching at 1680 Kbps, a significant increase but still slow by my expectation.

Then they scheduled a port reset and told me they'd call back when it happened (they haven't yet).

In the meantime my data rate has slipped back to 1124 Kbps.

I've read quite a few posts about central splitters. Problem is that from the outside junction the phone lines disappear into the wall of the building (4 level apartment)

and I can't find any internal sign of wiring other than the jackpoints. Is a central splitter still feasible and if so any equipment recommendations?

They also had me unplug my Sky digital box (the phone cord). Is that supposed to be a permanent situation?

Thanks again.

cr250bromo

222 posts

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#141617 30-Jun-2008 18:40

I used to live in an apartment and got Jetstart (128kbit!) back when a self install wasn't an option, ie Telecom insisted it was done by an installer with a central splitter. The installer found the first jackpoint in the apartment, installed a splitter behind it and then fitted a new jackpoint next to it for the DSL, so I'd guess they'd do something similar for your apartment.

A central splitter install is usually done by a Telecom/Chorus tech and isn't cheap ($99+). This may not solve the problem though, ie it could be between your apartment and the street cabling... Any neighbours geeky enough to compare ADSL sync speeds with :), if you could find out what other people in the building get it could also give you an idea of how good your connect rate is.

xpd

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#141621 30-Jun-2008 18:46

I had the similar issue of where after a restart it would get a decent rate then drop to something crap.
See my post "Slow speed driving me nuts" for pretty much full story....

Gavin / xpd / FastRaccoon / Geek of Coastguard New Zealand

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pcrosley

49 posts

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#141646 30-Jun-2008 19:51

Xpd,

That is a pretty depressing history! What is the situation now over a week later?

pcrosley

49 posts

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#141649 30-Jun-2008 19:54

Never mind! Sorry, I just re-read your earlier post that you still have over 6Mbps!

Now I just need a tech to test every cabinet between me and GDW2!

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

xpd

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#141677 30-Jun-2008 21:01

Heh yeah was an interesting lesson ;)

Guess I was just lucky that the last guy they sent out actually had a clue to trace the issue back. Was odd how none of the other techs could see the issue though.... good luck with getting your connection sorted however :)

Gavin / xpd / FastRaccoon / Geek of Coastguard New Zealand

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cyril7

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#141766 1-Jul-2008 08:13

Hi Powel, the tech will/should be able to determine what cables are where and what order they string from jack to jack, he will use a tone sounder to trace through the lines. Same goes for the line from the demarc. If there is room in the demarc he will most likely place the filter their, otherwise he will need to find somewhere inside.

You should express to him that you are only getting 1Mb/s on a 26dB attenuation, this hopefully will alert him to look for issues. Once he seperates the line at the demarc hopefully he will test he line from there, if its not up to expectation then he will work his way back down the line. Best hope (its only a 2km line so should be easy) is that there is only the pillarbox at the property entry and most likely a single local distribution cabinet between you and the exchange, any extras would be the result of breakages or extentions.

At least by installing or instruction to install a filter if the line does not comeup to mark you can clearly place it back in Chorus's lap to sort, they cannot keep insisting your house wiring is at issue. Just to repeat a reasonable expected speed on a 2km line is around 6Mb/s for ADSL1 and around 2x that for ADSL2+.

Cyril

pcrosley

49 posts

Geek

#141925 1-Jul-2008 15:39

Thanks Cyril!

Always good to know what catches the ear of these guys!

Telecom called back to say the port was reset (but my data rate remains 1128 Kbps). They said do the Jetstream speed test for 3 days and if it doesn't improve they'll schedule a techie.

I don't know how 3 days monitoring is going to increase the speed, but we'll see what they say tomorrow night!

pcrosley

49 posts

Geek

#144452 8-Jul-2008 11:12

Wow!

Telecom showed up this morning and 5 minutes later I'm at 8.5 Mbps!

Turns out that the phone line for the building's lift was connected to my terminal block!

Not any more, that's for sure.

Now we'll see if it stays this fast, lol!