How to Diagnose an ADSL/2+ Broadband Fault
Your first step should be to use the ‘Major Service Outages’ checker (you’ll have to be logged into the customer portal for this link to work) to see if there is a known issue in your area that could be affecting your phone or broadband service. The checker can be found under
Connectivity >Broadband > Major Service Outages
The second step would be to run a service line test via your Control Panel.
First you need to find the connection you are looking to test, especially more difficult if you have multiple connections with us. You can do this under the ‘Connectivity’ section of your dashboard.
Go to: Connectivity> Broadband > My Services
From the “My Services” use the search bar to input your broadband line number (CLI)or postcode to locate the service and then click on ‘View Details’ button.
From the four options at the top of the view details screen, scroll across to ‘Diagnostics’ to run the service line tests.
Understanding your Sync Information further
Sync Status Information
This shows you whether or not the circuit is connecting to the internet. If the connection is not in Sync, then it is worth checking the router/modem to ensure an Authentication issue is not causing the drops. If the router is not in Sync, please complete the form at the foot of this page, which will escalate this to Openreach for an engineer to attend.
Sync Speed (Kbps)
This shows the current connections upload and download speed in Kilobits per second (Kbps). Note: If concerned you can check this against the speeds demonstrated for your service type.
SNR Margin Information
This is the Signal to Noise Ratio. It shows noise on the line in decibels. If this figure is high and the broadband is unstable, we would advise you to check the routers cables along with a check on the PSTN line to determine if there is noise or interference.
Here's an example of what's good or bad dB Loss:
- 20dB and below is outstanding
- 20dB-30dB is excellent
- 30dB-40dB is very good
- 40dB-50dB is good
- 50dB-60dB is poor and may experience connectivity issues
- 60dB or above is bad and will experience connectivity issues
Attenuation
1. A gradual diminishing in the strength of something.
2. physics A reduction in the level of some property with distance, especially the amplitude of a wave or the strength of a signal.
This is the amount of signal loss between the modem and the broadband equipment. Check for interference from nearby devices such as radio's, PCs and damaged cables etc. Try moving electronic objects away from the Broadband equipment and replace old cables if any are found.
MTBE (Seconds)
Mean Time Between Errors – If this shows no results there are no errors seen on the line.
BRAS
Stands for Broadband Remote Access Server and this result is actually depictive of the maximum data throughput possible on the line.
Max Stable Rate (Kbps)
This is the maximum stable sync speed and is set when the line is first installed.
Copper Line Test
Carries out a copper line test to test aspects of the actual phone line. This will cause the line to drop sync for a minute or so. It may report back that an OR (Open Reach) fault will need to be raised with the provider of the PSTN line. Sometimes just running this test can fix some fault conditions.
IP Profile
Further detailed information can be found here.
In summary however, The IP profile is a limit put in place calculated from your sync speed, minus an allowance for various protocol overheads. The profile is applied at the BT bRAS to restrict the downstream data traffic speed on the backhaul between the bRAS and DSLAM.
Profile
The bandwidth allocation in min-max for both downstream and upstream. UC stands for Uncapped and is the typical setting for upstream although with ADSL2+ you’ll normally get in the region of 500k-2Mbps.
INP
Is an Error Protection method which helps prevent the loss of data in the event of noise bursts by using a retransmission buffer at the physical layer.
Interleaving
An error correction method, increased when there is noise and interference on the line to avoid errors but impacts speed. The lower the faster but less stable.
Target SNR
The target Signal / Noise Ratio. For the line. This is adjusted depending on the native noise on the line.
TAM Test (Test Access Matrix)
It can do a look in and a look out test to
determine problems in the system.
Modem Result
Similar to sync test, checking to see if the modem/router is present and responding
DSL Result
Simple test to check if the line is DSL enabled and live.
ATM Result
Asynchronous Transfer Mode – Packet switching test
PPP Result
Point-to-Point Protocol test
Carrying on your Diagnostics
If your service is showing ‘Out of Sync’, you can complete some onsite diagnostics with the router or remotely with the customer. Below are some tests you can run to help further diagnose the issue. More often than not, these steps can also help to restore service:
- Check that you have power to your equipment (Router)
- Check any equipment that’s connected to the telephone line - Telephones, Router etc.
- Restart the broadband equipment by turning the power off for thirty minutes and powering back on; this will ensure your connection is properly reset.
- Make sure all the cables are correctly connected and haven’t become loose.
- Plug a telephone into the socket and check for any crackling or interference on the phone line. If there is, please raise this with your PSTN provider.
- If you’re using Wi-Fi, check your connection is working correctly. Have you another device you can test this from?
- Test with a different broadband router if you have one available.
Still Unable to Connect?
You raise this to us as a Fault through your Control Panel using the options at the bottom of your service test page.
If for any reason the service line test comes back
with an error message or for any reason the ‘Raise Fault’ function isn’t
working, please use the visit Help Centre link at the bottom of the left-hand
side menu on the dashboard.