ADSL cutting out, yet again

The thick twin flex cable is a "drop wire". They sometimes get their insulation rubbed away by trees.

On a "normal line" hanset onhook......the voltage across the 2 wires should be 48-55volts.....as a reference you should read about 40-70mA across these same points (it varies with cable lenght)

Off hook the Voltage drops to around 10volts

....there are other systems out there that give different reading which is why I offered the "NORMAL LINE" scenario.

On the fault reporting number.....Not that it makes things much faster....0800375375 then somewhere there is an option to select "my modem sync light is not on" or somthing like that......you then get routed to the line fault people and not the ADSL support people......these guys are able to do the tests as described earlier in this post.

Gnome, Sounds like your line is aerial cable fed....open to the elements! they need to do a descent line test here and if its clear they need to work back from your place. Noise from a loose connection is almost imposible to test for via the helpdesk. But noise from moisture and foreign contact will certainly show up.
 
....fairly obvious miss here....also check for dirty plug point connections.

Dial a digit on your phone then wiggle the jack connections....if you have a dirty connection, you hear it become scratchy. Then the contacts need to be cleaned or replaced.

You does however seem to be outside the buiding as you mention weather.
 
Well my line is officially screwed, it has a voltage of about 7volts with NOTHING connected to the line and it also has no dial tone (yet the Adsl still works :D ). It did go off for a while (the voltage went as low as 1volt.

Obviously somethings screwed.

Btw. The house is very old (all the houses in this area are old) but the guy who built it ran CAT3 all over the place, which is why we have the DB thing outside, anyway I just rechecked the connections, the wires from the CAT3 connect to a chocolate block inside my house and then I connect that to a telephone panel (type that bolts to the wall) using CAT5, the voltage reading from the Telkom line outside has the exact same voltage as inside, no rust and the cables are still in pristine condition even though they are old, also the panel to chocolate block has worked for about 3 years now but to be sure I checked it with the multi-meter 0.2ohm resistance, so it's working fine.

The problem isn't likely on my end. *sigh* this is so annoying, just 6months ago the DSLAM broke (no dial tone no ADSL, yet it synched), and it feels like that all over...

My router also reports CRC errors like no tomorrow...

EDIT: oh yeah and the SNR Margin and Line Attenuation jump around, usually it's Downstream SNR Margin: 40dB Line Att (I'm sure about SNR but the Att. might have been something else): 20dB but now it jumps between SNR of 15dB to about 30dB (every second it changes), Line Att. seems more stable tho at 30dB...

LOL news server still runs at full speed tho, just disconnects every 30mins or so...
 
Last edited:
@Kasyx: It's possible that you may have more than one problem with your line. You should probably look into the large attenuation figure first as this might be causing the second problem indirectly. Personally I would first try to reduce your line speed to 2Mbps to see if this helps as it may be a very frustrating and time consuming exercise to get Telkom to repair it to your satisfaction.

A downstream attenuation of 19dB would give an estimation of the distance of ~1.4kms (19/13.81). As Leftfoot mentioned the V-Side telephone wiring which is exposed to the wind and rain is the biggest source of problems. If there is a line fault that is causing the router to report a downstream attenuation figure of 36dB then it could be at one of the joints on the poles etc. What brand of router are you using? Do you maybe have another router that you can use to confirm the attenuation readings. If you play around with the telephone on and off hook switch does this change the attenuation or noise margin readings at all. Maybe you can just leave routerstats running in the background and fiddle around with the phone.

Regarding the crosstalk problem. Do you think that there are any other ADSL or data connections to businesses like an ISP etc. running over the same bundle of wires leading to your residence as the interference seems to be happening right across the ADSL spectrum. This is why I suggested that this interference might be coming from the E-Side wiring from the exchange but I could be wrong.

@Leftfoot: The Americans seem to refer to the E-Side as F1 and the V-Side as F2. The pair I was referring to regarding crosstalk is in fact the F1 (E-Side) and not the F2 (V-Side) pair.

Here is a short primer on telephone networks (US ones!) for anybody that's interested - there is also an interesting link there about wireless local loops, the technology that Neotel has been promising but hasn't as yet delivered.
http://www.privateline.com/OSP/No.html
 
Leftfoot said:
Cant say I have heard of an F2 pair. Suffice to say that Telkom try to build in 25% spare capacity for faults and future growth.

A standard cable cable pair has:
- an E-SIDE (from Exchange to SDC-Street distribution cabinet
- a V-SIDE (from SDC-Street distribution cabinet) to the terminal equipment

The E-side is usually pressurised to resist water penetration
The V-side is not pressurised an has many connect points and potential problem sources. (trees rubbing through insulation, animals eating insulation, bats urinating and corroding connections...the list goes on)

9 times out of 10 the problem will be on the V-SIDE

In order to change your pair the whole way the tech needs to divert in at least 3 places (the Exchange -MDF, the street box -SDC, and the Local Distribution Point - DP).....can also be as much as ten points if your line in aerial cable fed.
Click to expand...

Nice post ! - Wish the field units would all receive the 3m dynatel 965p and sunrise sunset adslx testers - they provide REAL diagnostics and it erases all speculation (which wastes 66.67% of normal problem analysis time).

In my case the problem had been on both the E-SIDE and V-SIDE (40 year old cables) - but i'm going good now ..
 
Last edited:
Thanks Yotch for the F2 info. I am not familiar with US networks, Americans always seem to want to be different (VHS-BETA VIDEO, PAL-NTSC TV). I know in some European countries, a particular premesis could be fed by up to 3 E-side cables....all permanently pe-wired for redundancy (less work for the tech).....Sadly, not the case here in SA. The nature of our lanscape and distances etc make costs prohibitive.

I agree Mr Nuts, there are a lot of Telkom Techs that dont like to/dont know how to use their issued test equipment and rely solely on their dispatchers remote testing facilities. I personally used Sunrise/Sunset ADSL/ISDN testers and I frankly dont know how techs operate without using them. There are however some brilliant technicians that really know the score and sort things out "old school" using test equipment. That said however, some test equipment units cannot be used on lines anymore as terminal equipment has become more sensitive and prone to damage should those units be used....(thinking about Meggers in particular)

*Gnome*....sounds to me like you have a "low insulation" or partial short circuit on your line (explained by the low voltage and no dial tone). ADSL can work through this type of fault. Of course a "broken DSLAM" has been known to display similar characteristics. Somtimes this will cause your line to "trip" on incomming ringing or even ring engaged. Incomming ringing can also somtimes "burn" off the fault...but this is only temporary and the fault will re-occur. Best to have a fault on the line when the tech arrives.....at least then he knows whats happening. Seems the fault is beyond your premesis.
 
Code: 
Noise Margin (Upstream) 	12.0 db
Noise Margin (Downstream) 	-3.0 db
Attenuation (Upstream) 	18.5 db
Attenuation (Downstream) 	54.0 db

This is during a rainstorm, not a day after 3 different Telkom technicians checked my line and told me it was working fine again.

I hate you Telkom, I hate you so f*cking much.
 
Leftfoot said:
I agree Mr Nuts, there are a lot of Telkom Techs that dont like to/dont know how to use their issued test equipment and rely solely on their dispatchers remote testing facilities. I personally used Sunrise/Sunset ADSL/ISDN testers and I frankly dont know how techs operate without using them. There are however some brilliant technicians that really know the score and sort things out "old school" using test equipment. That said however, some test equipment units cannot be used on lines anymore as terminal equipment has become more sensitive and prone to damage should those units be used....(thinking about Meggers in particular).
Click to expand...

Well, I had a doozy at the house 2 days ago. He didn't even know how to get his own router to sync! He had to call in the area manager to help him. Then I find the area manager has never heard of the ping command and doesn't have a clue what it actually tells him. Thus, inspite of my ping to various local Saix and Telkom servers being well over 150 when they should be 40 my fault was closed "because you can download at 50kbps!". I really feel Telkom should train their staff properly. In the name of all that's holy can you be an area manager in charge of repairing ADSL and not know what "ping" is?

For the record I have now escalated this through a very helpful lady called Lydia at the Customer Complaints section. I'm not holding my breath BUT she knew what ping was and expressed her extreme dismay at the 2 clowns who were at the house. We'll see what happens, if anything. My ping is still nearly 200 as I'm typing this.
 
PCTECH said:
Well, I had a doozy at the house 2 days ago. He didn't even know how to get his own router to sync! He had to call in the area manager to help him. Then I find the area manager has never heard of the ping command and doesn't have a clue what it actually tells him. /QUOTE]

...welcome 2 the New South Africa :D
Click to expand...
 
Training is certainly a huge issue with Telkom. They insist that they can send appy's on one week modular courses to develop their skills.....it just dont work. A lot of Telkom techs are ok when it comes to physical concepts like ie "I can hear dial tone, or i can hear noise"......but when it comes to ones and zeros a lot of them fall out the bus.....not to mention inaudibel carrier signals.

I think Telkom would do well to go back a few years (1990)where they groomed techs in a 3 year course with a whole real live arena (Umhlanga rocks in my case) as a training ground with as many as 10 Trainers/specialists immediately on hand for support.....Sadly, I dont think this will happen, it was a hughly expensive concept.

There are two departments that In my opinion should be one. They are "Single lines" and "Data" (DAS)....the data guys are trained on one's and zeros and all things "pingy"....the Single line guys know what a copper pair is and what dial tone sounds like. But in our current enviroment of convergence - never the 2 shall meet....pity, because one can see the frustrations guys are having as a result. :(
 
I think Telkom would do well to go back a few years (1990)where they groomed techs in a 3 year course with a whole real live arena (Umhlanga rocks in my case) as a training ground with as many as 10 Trainers/specialists immediately on hand for support.....Sadly, I dont think this will happen, it was a hughly expensive concept.
Click to expand...

As far as I am concerned when I am paying for my line rental TWICE per month, I kind of expect them to have well-trained technicians, you know, so they can at least pretend the bullsh*t "ADSL Line Rental" I pay on top of my "Phone Line Rental" was benefiting me in some way.
 
Well just decided to post back, the telkom guy was here today, really nice guy, anyway he came in and plugged what looked like a old school multimeter into the socket that measures ohm values (or it looked that way), anyway with that he could immediately tell me the problem was 250meters away. We walked to our DB (which I rewired) and he tested again which he said determined the problem was less than 50meters away. Anyway turns out our cable runs underground (for about 10meters), after which it runs up a pole where the connections are made.

This "underground" cable isn't even buried all the way, and half the way to the pole you could see someone had mutilated the cable with what looks like a spade (it's in a garden so go figure). Anyway the cable that runs to our home has 8pairs but 4 weren't used so he just swapped some of the unused ones for ours.

Only one question I have that I wish to ask the those informed with the Telkom network (such as Leftfoot, he was right about it being a exposed/shorted conductor), now that the guy is finished the ADSL works again (reports Downstream Noise Margin: 40.5dB and Downstream Att. : 22dB), BUT when I pick up the phone I can hear noise, don't know how to describe it, it isn't scratchy or anything it's this constant humming noise in the background. I got it back at our old home also but it turned out to be the phone, but in this case both are phones are doing it (when it didn't before this incident). Also when I make a long (as in time not distance) call the noise stops after a while (say 5minutes). It's very annoying!

EDIT: Also my Billion 7300 router seems to have given up the ghost, the Telkom router (old marconi type) still works 100% but as soon as I connect the billion router it freezes up after 2-3minutes *sigh*
 
Last edited:
Hi Gnome,

Great to hear your tech used test equipment other then a screwdriver and a phone!

The hum you are getting is most likely another fault condition generated by the "Mutilated" cable. We call it an "Earth" fault meaning that at least one of the conductors in your pair is connected to the ground or the general mass of earth. The hum you hear comes from the fact that most electrical system are also earthed (neutral wires and earth wires being commeon on an electrical power supply system). If you had to measure the frequency of that hum it would most likely be 50hz - the same frequency as the electical power supply in SA.

My gut feel here is that the mutilated cable is still to blame and that the tech has diverted to a pair less faulty that the first pair you had. The test unit he was using does not easily locate an earth fault....you will most likely find that Telkom fault report/testing people (not the "KELLY TEMPS") will be able to pick up the fault remotely.

The fact that the hum comes and goes depends on how well it is connected with Earth - via a water droplet, mud, a worm:)

Solution for the tech - 1)replace the cable - expensive (2) cut and remake the the joint and seal it in resin kits they use.

Tip.....bury the cable deeper!:mad:

I would imagine that this would still have a negative influence on your ADSL line as I had a similar problem about 6mths back.

*if you have had lightning recently it it also a good idea to temporarily bypass any lightning protection you have or indeed anything that comes with built in lightning protection. These too can "blow" to earth and although most are designed to restore themselves, some remain permanantly connected to earth (in this case they need to be replaced)*.....just remember to put it all back when you are done.
 
Last edited:
Ok cool thanks for the advice, I'll call the ADSL tech support center and tell them to do a line test. As for the lightning filters, I skipped them to test the line, in fact I disconnected everything and just connected the phone with the same results.

Thanks again.
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X