Since I'm working in ISP bussines I thought i could do a little guide for you how to get better and more reliable connection. Most of those steps i describe are applying to DSL types of connection but some of them may apply to other types as well. I'll divide it into couple of sections .
in sync - device is synchronised with your line ( by common indicated by solid DSL light on the device)
out of sync - opposite of the above ( DSL either flashig with constant manner or off completely)
Modem/router in sync but you cnt connect:
Check if all the settings on the router are correct.Try to use wired connection ( if your using wireless). Contact your ISP for updated settings and a possible network issues. Quite often it is a fault of outdated firmware, so if possible try to upgrade firmware of the device
Device out of sync ( no DSL light):
Now here something has gone wrong big time. Your device cant get any sort of signal from the line. First try to move your device to a master phone socket. By common thats how it looks like:
Also try to disconnect any other phone sockets in the house.
If still out of sync check that ADSL microfilter isnt damaged by replacing it.
Another common issue is a damaged DSL cable. You may either replace it or if you dont have one try to connect it to ethernet port while making a call, if it will mute your phone that will indicate that the cable is ok.
Next step would be - assuming that previous ones didnt work - to move your connection to a test socket. Now picture above shows you an NTE5 socket. As you can see bottom half is removable. Inside you'll find a test socket:
The test socket allows you to overpass any internal wiring.
Only exeption of that is if you have an SSFP ( Service Specific Face Plate) socket:
That socket has an ADSL filter built into it - so theres no need of using an external one - and dosent have a test socket.
So now at this stage if your device is still out of sync grab a phone and call your ISP and do some bulling .
90% of examples of out of sync connection in my experince was fixed by following the steps metnioned above.
Intermittent connection/ slow speeds:
First - if your using a wireless connection - try your connection with a ethernet wire and see if still is the same.
Second ring your ISP for updated settings for your device ( if there are any). Then try to reset the router. Best way of doing that is by going to router confguration page , ie. for Netgear it is http://192.168.0.1 and in there should be an option to revert to factory default settings. IMPORTANT: do this only when you have a wired connection between your PC and the router beacuse this step will most likely remove any wireless configuration. Then reconfigure it with the settings that you got from your ISP. If above doesnt work try to follow the steps in out of sync section. If those wont help either contact your ISP.
In all cases when you are contacting your ISP have the device reset and reconfigured and on master/ test socket ( whichever applicable in your case) and any other phone sockets disconnected.
When rigning your ISP try to find out couple of things which are:
What is your current connection profile - it simply migt be setup to some fixed rate (ie 2 Mbps) and no matter what you do you wont be able to go higher on speeds.
What is your line Attenuation/ loop loss - this value determines how far away you are from the exchange. Critical value for UK is 63.5 . Anything above that isnt capable of giving you any reliable connection. You may get a connection but it will be droppingout ie. every five minutes and speeds will be somwhere around dialup connection
What are your SNR ( Signal Noise Ratio) margins - this determines whats the quality of your line . Critical value for UK is 6 dba. So ie. if atm your getting 2 Mbps connection and SNR is 6 you most likely wont get any higher speeds beacuse of too much niose on it. But if you have 2 Mbps and SNR is around 15 or 20 you may persist on increasing your speeds.If after an upgrade you'll be getting disconnection issues try ringing again and check what is your SNR at that stage
This Giude mostly applies to DSL UK based systems but I hope everyone will find something handy to improve their connection
Hope it helps!
P.S Any questions??