Spontaneous disconnections and fluctuating speeds

Dear all,

The more I read around about bb, ADSL, exchanges...the more overwhelmed I get with all the various router statistics and diagnostic figures about noise, attenuation etc. I would be grateful if someone could crunch my stats and let me know if what I am experiencing is normal for my exchange and ISP?

I used to have my line rental with BT and calls + bb with AOL. In Nov I took up AOL's deal of switching over my landline to them too and have one simple bill. So atm I pay £13 in line rental and £7 for unlimited bb and unlimited calls (i've been with them for years, hence the free upgrades to unlimited).

Since doing this, there was a week when there was no dialtone and incoming calls would give an 'engaged' tone...although ADSL would work. Several calls to tech support seemed to resolve that...apparently it was a problem at the exchange and not in my line.

I usually get 5-6 Mbps downstream...but since the switch I get 3-4 Mbps according to speedtests and sometimes I lose connection and speeds dwindle to 0.5-0.6 Mbps. What could be behind this?

Router stats:

Link Information

Uptime: 0 days, 13:40:07
Modulation: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 960 / 5,803
Data Transferred (Sent/Received) [MB/GB]: 172.06 / 2.41
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 24.5 / 43.0
SN Margin (Up/Down) [dB]: 9.0 / 8.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 62 / 0
FEC Errors (Up/Down): 0 / 2,197,818
CRC Errors (Up/Down): 0 / 5,528
HEC Errors (Up/Down): 0 / 4,638



Exchange details:

BT ADSL broadband availability

You are connected to the Cambridge telephone exchange.

ADSL is available in your area
Your exchange is also enabled for ADSL Max services
Your exchange is also enabled for ADSL2+ services

According to BT Wholesale, houses at your postcode should be able to support

up to 2Mbps via ADSL
4Mbps or greater ADSL connection via ADSL Max
5.5Mbps or greater via ADSL2+
Standard ADSL RAG results

You can receive 2Mbps ADSL
You can receive 1Mbps ADSL
You can receive 512kbps ADSL
You can receive 256kbps ADSL

You are approximately 2.31km from the exchange. Note that this is the straight line distance - the actual cable length will be longer!



Is there any other diagnostic I should run to give you more info?

Many thanks!


PS, running router stats at 1min intervals to show 3000 points per capture....will post tomorrow once it's got 24hrs of stats recorded.

Edited by deleted (Mon 23-Jan-12 18:21:59)

In reply to a post by fsa297:

Modulation: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 960 / 5,803

You are running on ADSL2 only. You should be on ADSL2+ (G.992.5) and getting 7 Meg @ 6 dB NM.

Is this a simple matter of AOL activating something on their software to enable me to get ADSL2+? Or is it a hardware thing? My router is ST585v6sl...i think that can handle ADSL2+

Edited by deleted (Mon 23-Jan-12 19:49:31)

No, it's automatic, as a result of your router negotiating with exchange.

Try disconnecting and see if it changes.

Many thanks for your advice. Restarting the router helped...it's connected on G.992.5, but the downstream is still similar:

Link Information

Uptime: 0 days, 0:04:33
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 965 / 5,589
Data Transferred (Sent/Received) [KB/KB]: 56.00 / 67.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 24.5 / 42.5
SN Margin (Up/Down) [dB]: 8.5 / 9.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 303 / 79
CRC Errors (Up/Down): 36 / 1
HEC Errors (Up/Down): 9 / 1


Does that mean that's probably the best my line can do?

Have you removed ring wire? Tried diff filters? Are you using the standard ADSL cable between socket & router, as supplied? Are you plugged into master socket? What phone extensions have you?

Get the stats with the filter plugged into test socket behind faceplate of master socket, with no phone connected.

SN Margin (Up/Down) [dB]: 8.5 / 9.5

And when you re-connect via the test socket, as XRay has requested, please immediately check you router statistics. Looking at the above, you could be on a 9 dB SNRM target and a 6 dB target margin may be possible -- which could give you an approximate extra 500Kbps download sync.

Different filters yield similar results. I'm using the standard ADSL cable as supplied. Router is directly connected to the master socket...no phone extensions in use. (phone is connected to the filter).

The master socket is the old type without the faceplate...which is strange considering the line was fitted when I moved in last year. Am I allowed to remove the ring wire since this is the old style socket?


This is with a different filter and no phone line:

Link Information

Uptime: 0 days, 0:00:19
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 1,020 / 5,677
Data Transferred (Sent/Received) [KB/KB]: 1.00 / 1.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 24.5 / 42.5
SN Margin (Up/Down) [dB]: 9.0 / 9.0
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 1 / 0
FEC Errors (Up/Down): 176 / 0
CRC Errors (Up/Down): 32 / 0
HEC Errors (Up/Down): 9 / 0



On the last upgrade they provided a new dsl 2640r, but since my ST585v6sl (also from them in the previous year) seemed to be working fine, I didn't bother changing. Is the D-Link one supposed to be better at ADSL2+ than the ST one?

Edited by deleted (Mon 23-Jan-12 21:58:30)

In reply to a post by fsa297:

The master socket is the old type without the faceplate...which is strange considering the line was fitted when I moved in last year.

That shouldn't be if it was installed by BT. Think you can get BT to fit a modern NTE5 for free to regularise it, particularly as they failed to do it last time.

The error count would seem to be high, indicating that there might be something else going on, when using the phone at the same time as the router is in sync, do you get any noise on the line ??