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[yousaf465]

What might be the cause of the this variation. Modem is ZXDSL CII 831. ONU is hardly 600m from my modem.



Line stats

SL Mode Setup     G.DMT   Annex Type Setup     ANNEX A
Current ADSL Mode     G.DMT   Current Annex State     ANNEX_A
ADSL Up Time     0:09:33   System Up Time     4:58:24
Downstream Rate     6016    Upstream Rate     1056
Latency Type     Interleaved   Line Coding     trellis on
SNR Margin US/DS     7.0 / 27.0    Line Attenuation US/DS     7.5 / 10.5
Power US/DS     12.0 / 19.5    Attainable Down Speed     12064
Link Up Times     0   Line State     Showtime


Statistics    Downstream    Upstream
K     189    34
R     16    12
S     1    4
D     32    8
Super Frames     44776    44776
Super Frame Errors     0    0
RS Words     3044768    761192
RS Correctable Errors     32    2132
RS Uncorrectable Errors     0    888
HEC Errors     0    409
LCD Errors     0    0

[roseway]

It's almost certainly some kind of line fault. Assuming that you have an NTE5 type of master socket, you should connect the router to the test socket to eliminate any internal wiring from being the cause of the problem. Then, if you still see the large spikes of interference, you can be fairly certain that the fault is external.

Do you hear any hiss or crackling on the telephone? If you do, the best course of action is to report this as a voice fault to whoever you pay your line rental to. Don't mention broadband, because this will only confuse the issue, and fixing the voice fault will most likely fix the broadband fault at the same time.

[SlowConnector]

It's almost certainly some kind of line fault.

What makes you think it could be a line fault? The line could be perfect, but maybe the router is picking up RFI/REIN from a piece of electrical equipment situated in a nearby room.

If the problem is due to RFI, then there will be no reduction in the spikes of interference when you connect to the master socket.

[yousaf465]

During and after power failure. you can see the SNR is improved during power failure.

[SlowConnector]

I am not sure what you mean by power failure. If you mean your electricity supply was cut off, wouldn't your router stopped as well?

By the way, do you hear any hiss or crackling on the telephone? Have you attempted to collect router statistics when connected directly to the master socket?

Please give us some more information if you wish us to help you.

[burakkucat]

ONU is hardly 600m from my modem.

Please clarify the above phrase. 

I expand it to read that the electrical distance between the DSLAM (or MSAN) and your modem/router has been measured to be 600 metres.

Are you using the abbreviation ONU (Optical Network Unit, perhaps?) to signify the exchange located MSAN (or DSLAM)?

[kitz]

I too was puzzled by the phrasing.  For the sake of other members the OP is in Pakistan not the UK.

edit after quick google

I think the ONU may be the equivalent of our MSANs?

(ONU)/MSAN(Huawei )

[burakkucat]

Thanks, Kitz. That is fairly conclusive. So we can read MSAN for ONU.

A minor point but it does help to know where a forum member is located. Without that knowledge, we automatically default to assuming BT Group or other UK based CP equipment.

[yousaf465]

Yeap, ONU means http://en.wikipedia.org/wiki/Optical_network_unit.

The router and PC are connected to UPS http://en.wikipedia.org/wiki/Uninterruptible_power_supply

The graph show the variation during a phone call, it went on from 10:22-1023, quite incidentally it was phone company's lineman on the other end.  8)

[burakkucat]

Ah! In the light of the latest graph and information, I would now suspect that a HR (High Resistance) fault is developing in one of the joints in the pair. 

[yousaf465]

Ah! In the light of the latest graph and information, I would now suspect that a HR (High Resistance) fault is developing in one of the joints in the pair. 

In layman's terms, the joints need to repaired ? 

[burakkucat]

In layman's terms, the joints need to repaired ? 

In view of what you have previously mentioned, I would carefully check each joint in the cable between your modem and the ONU. I suspect that one of them may be going faulty --  so to dismantle that particular joint and then remake it should prove to be a satisfactory fix. 

[yousaf465]

According to Lineman he has "refreshed" the line. I don't think so  , The graph show SNR before, during and after a call. The Bump at 11:05 is due to power outage.

[kitz]

The large dips would clearly seem to indicate a HR fault as suggested by B*cat.

>> According to Lineman he has "refreshed" the line.

If the terminology is similar to the UK then a simple refresh of the line wont clear a HR fault.  High resistance fault is something wrong on the physical telephone line - usually corroded joints or worn cable.

As mentioned by roseway this is a telephone (voice) fault not adsl.       


-----------

During and after power failure. you can see the SNR is improved during power failure.

and

The Bump at 11:05 is due to power outage.

You may well have a separate issue of a small amount of REIN.   Although your router stays up because of the UPs, its likely that the absence of many other electrical items that would normally be switched on and working, means less EMI and therefore your SNR will be slightly better.   
It must be said though that its not unexpected for a router that is still attached to a UPS device to show a slightly better SNR under such circumstances.  The line that is still up in the absence of other lines will clearly be subject to less crosstalk (FeXT & NeXT) and in-evitable interference from many electrical items that would normally be powered on.

[yousaf465]

Thanks. 

Should I refresh/fix this box.