Why you can't get maximum Telkom DSL speeds

MickZA said:
Continental drift perchance :D
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Must be :D

My sarcasm and fighting hardly ever helped. Even after I bitched and moaned till them "fixing"the problem resulted in their equipment going from 4.2km to 3.2km in one session.
 
This is all fine and well but why can one get say 80-90% on a 4MB line, then downgrade to a 2MB line and again only get around 60-80% on the 2MB line. Surely if it could manage close to 90% on a 4MB then a 2MB line should be humming away at near max speed except of course for the overhead.
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kianm said:
Did you consider the transmission overhead?
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Yes, but I was getting to was the following. I had a 4MB line installed at my mom's place. Max speed on that line was around 400K on downloads which was good and essentially the max for the line. Average speed however was closer to 350K with many a day where it battled to break 300K. And this was in the wee hours, line was essentially useless from around 18H00 until after around 22H00.

We then downgraded the line to a 2Mb as all she does is read/send mails so a bit of a waste for a 4MB line. One would expect the performance to go down by around half but this was not the case. On the 2MB line max download speed now is around the 140K mark [35% that of the 4MB line, one would expect ±50%] with the norm being in the region of 100-120K [34% of the average on the 4MB line].

Contacted Telkom and one of the reasons given by them was the copper as per this article. So my question to them, which went unanswered, was whether they downgraded the copper as well as it seemed to work just fine on the 4MB line so what has changed?

So my point being, it's not just the copper that is to blame, there is more to the p****s poor speeds people have had to live with.
 
How do you determine how far a house is from the nearest exchange when deciding to buy a house?
 
sometimes im glad I don't get more than 4mbps. then I might 'want to need' 10mbps. last I remember its quite a jump in price between the two. don't utilize my line as it is.
 
Problem comes in when you can get 10mbps and you pay for 2 months dont even get 5 mbps then go down to 6 and still struggle....im 600meters away from the main city centre so i cant see why my speed is so bad. Had the telkom guys there and they say max is 6mbps.
 
I reckon, give it 2 or 3 years and we'll see MSAN programs being aborted. Theft of batteries and metal from the current MSAN's is rife and making it uneconomical.

As for the copper issue: Copper itself does not really degrade as has been banded around this forum. The insulation and connections such as "Scotch-locks" and Krone/3M connections might well do. Hence maintenance and "moisture free" connection units is more key.

The copper ADSL signal characteristics are typical for 0.4mm copper that is found in SA underground cables. Overhead aerial cables are 0.63mm and indoor cabling is 0.5mm. These differences in cable diameter can produce "reflection" due to impedance differences to ADSL signals therefore influencing ADSL quality.

The table in the article is typical for copper as a whole and no necessarily Telkom's infrastructure.
 
Leftfoot said:
The copper ADSL signal characteristics are typical for 0.4mm copper that is found in SA underground cables. Overhead aerial cables are 0.63mm and indoor cabling is 0.5mm. These differences in cable diameter can produce "reflection" due to impedance differences to ADSL signals therefore influencing ADSL quality.

The table in the article is typical for copper as a whole and no necessarily Telkom's infrastructure.
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Thanks!

What copper cables are used in other countries? Is there an international standard?
 
Please can TELKOM explain this....

I am currently on a 4Mb profile but my maximum speed i can download is around 3Mb (400KB/s). Previously on the same line i had the 10Mb profile active and my download speed was around 8Mb (950KB/s). So i have now out lined the both services that i used on THE SAME LINE.

5 months ago i downgraded my service from 10Mb to 4Mb. In essence this was only a speed downgrade and not any physical hardware changes. Now im on the 4Mb profile but my maximum line speed achieved is 3Mb. I know my maximum line speed that i can achieve is 8Mb but why cant i get my full 4Mb speed on my 4Mb line. STRANGE HEY!!!

I asked telkom about this and they say my distance from the exchange and noise play a roll in the speed. BUT from day 1 that i downgraded from 10Mb to 4Mb i have only been able to get 3Mb max.

PLEASE EXPLAIN THIS TELKOM????
 
MickeyD, from what I know is that SA followed British Telecom reticulation examples in early years. The main difference eventually that in this country we allowed the local loops to extend to the limits of analogue transmission (5km norm). In my experience copper diameter over short distances has little or no influence, but over greater distances the SNR is less, due partly to the influence of "reflected" signals ( change in copper diameter or bad interconnectivity between cables)

So in Europe, it was easy to have short distances from the exchange to customer due to the geographical nature of the the land and concentration of the populace. So sorted distances resulted in hight speeds. Make no mistake though, rural UK still has internet speeds lower than ours in a lot of cases.

MSAN's are now springing up everywhere now in an attempt to shorten the local loop. But I have it on good authority that, particularly in Gauteng, that these are being pilfered at an alarming rate for batteries and other metals. This to the extent that some even have armed guards protecting them.

Although MSAN's are a great idea, in this country I think the only solution will be wireless.
 
@Leftfoot: I know that the yanks were very surprised by the quality of the copper that Telkom was using when they were involved in Telkom (SBC). My mates at Aberdare were surprised when they were queried about this!

I agree with your post, especially regarding cable lengths.
 
They should explain to me then WTF happened to my line. I used to be able to connect over 8Mbps, according to my modem's attenuation and SNR calculations. Then at the beginning of the year some idiot came and "worked" on the lines, screwing it up so much that It could barely stay sync'd at 4Mbps... I had technicians come out 7 times... 7 BLOODY TIMES.... and its still like that...
 
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