DSL line test criteria

douglasman

Does anyone know what the actual criteria are for passing for RADSL and ADSL. I already have Eircom Broadband and by telnetting to the Netopia and typing 'show dsl' I can obtain SNR Margin and Line Attenuation information. Does anyone know what Eircom's threshhold for these passing/failing is. From what I can tell, nobody seems to be 100% clear on exactly what criteria makes a line pass or fail for DSL.

iano

Did anyone (Muck ??) post a reply here or elsewhere?

spongebob

I commented on how you could get the SNR ( Db Levels) data off a diagnostic on an Analogue modem , similar stuff to the Netopia data really....and do a kinda DIY line test . Others then provided beter data.

I think this thread below is what IanO was on about .

http://www.boards.ie/vbulletin/showthread.php?postid=1116620&highlight=lucent#post1116620

M

iano

Thanks for that.

My real questions are:
- What do Eircom consider to be an acceptable line for their ADSL in terms of Attenuation & SNR?

- Do these figures differ for the different levels of service (512 home, 1Meg, 2Meg etc.)?

- What is the minimum that they guarantee from an Eircom installation?

I have come across a situation where some routers will not synchronize but the Netopia thingy appears to connect (at a reduced speed?). Perhaps this is due to the line characteristics being marginal/out-of-spec.

thegills

One thing is for sure; the criteria are extra stringent compared to say the UK. The logic being to keep the failures high in order to keep all those poor b*stards on ISDN.

spongebob

BT will pass you for 512k as far out as 6KM , they own all the lines , sound familiar ? That allows 60 Dbm too.

OTOH Our useless lot will do a test that will normally fail you above 4.5Km as I recall and that is for 256k .

Is there anyone here with BB, however wheezy, who is over 4.5KM from their exchange ?

M

Richard Dower

I'm told i am about 4-4.5Km from the exchange here in Limerick. And i get speeds exactly the same as when i was less then 100 feet from the Roaches Street exchange.

iano

I'm told i am about 4-4.5Km from the exchange here in Limerick. And i get speeds exactly the same as when i was less then 100 feet from the Roaches Street exchange.

What is your attenuation and SNR (in dB)?

Gonzo

im 2.3km from my exchange and connect at 512k, however if I wanted to upgrade or get upgraded in the future to 1mb, would 2.3km be too far away from the exchange for this sorta speed? What about 2mb even?

Richard Dower

Good question...it's my understanding you have to be 1.5Km from the exchange for 1MB/2MB. But you could always try and see if you past the line test.

Richard Dower

Originally posted by iano
What is your attenuation and SNR (in dB)?

lol..if you tell me how to view those stats in the Zyxel 630 control panel i'll tell you.

thegills

I'm told i am about 4-4.5Km from the exchange here in Limerick

Can I ask which exchange??

Richard Dower

Roaches Street.

dogz

Eircom will only pass a line that is capable of 256kbps for a 512k dsl line. As far as i know this is less for esat but im not sure by how much.

iano

if you tell me how to view those stats in the Zyxel 630 control panel i'll tell you.

There is a "hidden" menu which has all of these statistics.

Check out the section "Advanced / 'Hidden' Features" in the following guide:
http://www.adslguide.org.uk/hardware/reviews/2002/q2/zyxel_prestige630.asp

Richard Dower

Ok, found it...the transmit noise margin is 25dB, the receive noise margin is 33.5dB
That what you need?