I've been having some issues with my DSL line and when AT&T did a line test they found a lot of noise.
The technician came out and tested the line up to the house and said it was clean. This means that the wire in my house is probably bad or has some interference.
I did all the wiring in my house since we built the house, but I'm not sure how to test the cable for noise.
Is there a tool to test this with? Or how do I determine if there is interference? Should I just run a new cable?
UTP cabling is usually tested with a cable tester that basically uses time domain reflectometry. Testers with this ability are somewhat expensive, so they are usually out of the budget of a home user.
A tester might also transmit signal on one conductor, and expect the signal to be returned on another conductor (requires a terminator which builds a loop). The electronics will compare the transmitted signal against the returned signal.
Simple testers basically just test the resistance.
Almost all good testers require either a terminator on one end, or something that builds a loop out of the various conductors.
This wikpedia article on Copper cable certification includes lots of details about various tests that may be performed.
This probably belongs on SuperUser (I've voted for it to move), but many common cable tester tools will provide good information on the quality of the line, with regard to faults, signal-to-noise, crosstalk, resistance, etc.
That said, a good cable tester would probably be a bit of an over-spend for a home project like this. Maybe just re-do the ends and punch downs (the most common points of failure), and see if that helps first.
