General Discussion
  >> General Broadband Chatter


Register (or login) on our website and you will not see this ad.


Pages in this thread: 1 | 2 | (show all)   Print Thread
Standard User mjl123
(newbie) Tue 16-Sep-14 21:16:25
Print Post

HEC and CRC errors when phone rings


[link to this post]
 
Hi,

I'm pretty sure there's a fault on the line, but I'm not sure on how best to tackle it. The following happens when connected to the test socket as well as the normal front of master socket:

When the phone rings I get Upstream HEC errors and CRC errors and the "Error Seconds" count increases. The errors keep increasing until I answer the phone, but once answered they stop increasing. Also when the phone rings the downstream noise margin drops, but unlike the errors this stays lower until I hang up.

I've uploaded a picture of the graphs here

My stats:
Downstream: 1.656 Mbps
Upstream: 448 Kbps

Noise margin (Down/Up): 6.0 dB / 15.0 dB
Line attenuation (Down/Up): 60.1 dB / 31.5 dB
Output power (Down/Up): 17.9 dBm / 12.6 dBm

A bit of background:
When the line was installed last year (new build property) the openreach engineer installed the master socket where the developers had intended. I had trouble with broadband and got an engineer out who noticed the master socket was wired to an extension, and so moved the master socket to the right place. He also replaced the master socket with one with a built in filter. So I don't have great confidence in the internal house wiring from the developers.

I've tried taking the front of the master socket off and trying all extension points to make sure that the master socket is wired directly to the incoming line, and given none of the extensions work i'm assuming this is the case.

So my questions are
1) I'm assuming the errors aren't normal, but is it normal for the downstream noise margin to drop while on the phone?
2) It seems odd that the errors are only on the upstream, but the noise margin drop is only on the downstream. Is this odd?
3) Could this be an external fault, or is it more likely to be a problem with the internal wiring from the outside to the master socket?
4) If it's likely to be an internal wiring fault, would BT still be liable for this as it's their side of the master socket?
5) Should I report this as a broadband fault or a line fault?

Sorry for so many questions, any help would be much appreciated
Standard User Zarjaz
(knowledge is power) Tue 16-Sep-14 22:43:26
Print Post

Re: HEC and CRC errors when phone rings


[re: mjl123] [link to this post]
 
Nearly all lines will generate some errors when the phone is used at the same time. What fault actually occurs, if you are just trying to report that using the phone generates errors, then you are going to struggle.

Standard User RobertoS
(elder) Tue 16-Sep-14 22:49:56
Print Post

Re: HEC and CRC errors when phone rings


[re: mjl123] [link to this post]
 
My SNRM drops by about 1.5dB when the phone is in use. I believe that is normal, and that some are worse.

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 56.6/14.1Mbps @ 600m. - BQM

"Angels can fly because they can take themselves lightly." - G K Chesterton.


Register (or login) on our website and you will not see this ad.

Standard User adslmax
(knowledge is power) Tue 16-Sep-14 22:52:23
Print Post

Re: HEC and CRC errors when phone rings


[re: RobertoS] [link to this post]
 
Mine never drop. SNR stay the same when the phone ring or in use.
Standard User MHC
(sensei) Wed 17-Sep-14 00:43:40
Print Post

Re: HEC and CRC errors when phone rings


[re: mjl123] [link to this post]
 
Change in noise margin during ringing - yes it can happen, sometimes very small and sometimes maybe 1 or 2 dB. Nothing that you can do about it. If it start to get up at around 6dB change ten maybe there could be a fault, but unlikely in your case.

As extra noise is generated by the ring signal and it can be in the ADSL band then it is very likely that some extra errors will occur. Potentially more on the upstream as the data adjacent to voice is upstream.

Once the phone is answered the actual line characteristics/impedance changes which can also affect the ADSL signal and again it might cause a slight increase in error, or a decrease.

You seem to have checked your connections - one question though. What cable is used to connect extension to the master? Is the incoming connection to the master direct using BT CW1308 or is there something else? Can you get pictures of te cables?


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User mjl123
(newbie) Wed 17-Sep-14 13:41:33
Print Post

Re: HEC and CRC errors when phone rings


[re: Zarjaz] [link to this post]
 
I noticed call of duty lagging when the phone went, which prompted me to look into it. If it is normal to get CRC errors when the phone goes (even when in the test socket) then I guess it could just be coincidence (it does lag quite a bit normally anyway)
Standard User mjl123
(newbie) Wed 17-Sep-14 13:56:44
Print Post

Re: HEC and CRC errors when phone rings


[re: MHC] [link to this post]
 
Thanks for the reply,

I've uploaded a picture of the master socket with the front off, although I haven't taken the socket off the wall to check the wires going to it. Presumably it's just a case of popping those two screws out?

There's what I assume to be the extension wiring going to the front part of the master socket, hanging down just out of shot. These are orange, blue and white (with bits of blue).

The three other wires in the picture that aren't connected to anything are Green, White (with bits of green) and white (with bits of orange).

Silly question, but aren't the filters supposed to prevent the ring signal from interfering with the ADSL signal? Or does this interference occur between the exchange and the PCP / PCP and the house?
Administrator MrSaffron
(staff) Wed 17-Sep-14 14:01:50
Print Post

Re: HEC and CRC errors when phone rings


[re: mjl123] [link to this post]
 
Microfilters do the job on the lead to the phone to or the ADSL modem, they can do nothing about the extension wiring you have shown.

The presumption is that the orange wire is going to pin 3 on the small faceplate, and this is the ring wire which you can lift out of the connector e.g. http://www.thinkbroadband.com/faq/sections/radsl.htm...

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User mjl123
(newbie) Wed 17-Sep-14 14:07:47
Print Post

Re: HEC and CRC errors when phone rings


[re: MrSaffron] [link to this post]
 
Thanks Andrew, I get the error even when in the test socket (no extension wiring connected). Assuming the filter is working ok, would you still expect errors caused by the phone ringing?
Administrator MrSaffron
(staff) Wed 17-Sep-14 14:15:17
Print Post

Re: HEC and CRC errors when phone rings


[re: mjl123] [link to this post]
 
If the master socket is wired to the incoming line correct, then when using the test socket and you've proved the microfilter is not the issue (e.g. new one) then suggests could be a HR fault (High Resistance) on the line.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Pages in this thread: 1 | 2 | (show all)   Print Thread

Jump to