New RJ11 cable

There will probably be a significant lag time however before he understands your message.

Later on in the evening by any chance? The more people in your area on the net at the time the greater the impact on your speeds. Have a look at 'contention rates' to get a bit of an idea as to how it works.

It's also been known in the UK for ISPs - or maybe it's just BT - to assess your usage from the outset and traffic shape you accordingly. To avoid this practice, use the connection to the maximum from minute one onwards - stream some video from the BBC website then go away and leave it for a few hours.

The only time the cable between the wall socket and the router affects download speeds is when the dog chews through the cable, or the cat shreds it. Then your download speed drops quite dramatically to nothing. Otherwise, the cable will not noticeably affect download speeds.

Changing out the cable for one with higher-quality connectors and a better grade of copper will have an effect, on the order of about 0.001% if you are lucky.

I have been having this argument for months with people who take their audio seriously - having perfect pitch and being one of the 5% who has incredibly sensitive hearing makes a person learn about factors affecting audio quality in very short order, and years of experimenting proves that the cable doesn't have that much of an effect. Since audio signals and communication signals operate according to very similar principles (the old dial-up modems were also referred to as 'acoustic couplers' sometimes) the same logic would apply. Since ADSL still uses the legacy PSTN/POTS cabling with an additional carrier frequency to handle the data traffic, playing around with the cabling will have no appreciable effect, except possibly to make it worse. In fact, the actual router itself will have a larger impact than the cabling.

You might get better results by changing your DNS server settings and/or going to a more expensive contract with your service provider. Or a different provider.

By 'high current' you mean on the order of >350VA, anything less will not develop a strong enough EM field to be able to noticeably affect Ethernet, ADSL, or most others.

This scenario only applies in an environment where heavy machinery can be found.

CRT is a special case, since the fields developed by the focusing coils can be quite intense, but seriously - who the hell runs cables OVER their monitor?

There is error correction on either end of an ethernet line, right? But but a lot of cables are only twisted pairs and even a mains cable can cause interference in a twisted pair, correct?