If the lines are colored blue, orange, brown, and green, with striped versions, and they are twisted in pairs, then they are probably CAT-5 or CAT-7 ethernet wires, probably running in Power over Ethernet mode. Incidentally, one of the reasons that the wires are twisted is to counteract the very interference you are trying to create.
When you are talking about noise in the line, it is very important to specify the power spectral density (PSD) of the noise, which is just a fancy way of saying what are the frequency bands where you want the noise to be created and how much power at a given frequency want. This implies that you should first figure out if it is indeed and ethernet cable, and if so, what is it for. If it is an Ethernet signal, then you should check to see if it is using 10mb/s or 100mb/s. Once you have done that, there are tricks that you can do to cause the right type of interference, but keep in mind that waves on Ethernet are sqaure, not smooth like a single sine wave. This means that an Ethernet "radio" would have to be tuned to all the different radio channels at once to hear Ethernet "music" at the other end if it were based on FM. Therefore, don't expect a walkie talkie to do anything. If you kill the frequency in the Ethernet wave at the walkie talkie frequency, it won't matter, because all the other sine waves embbeded in the sqaure wave will work together to "cover the back" of the sine wave you disturbed. But there is something that might work. Simply find the cables that are used for data (look up ethernet diagrams on Google), and cut into them (be careful), and put some long UNCONNECTED wires dangling off the ends. The signal will see the dangling wires, run down them, hit the end and find out there is no were else to go, then come racing back to interfere with the other signals that are on the base wires.
-Chaud Lapin-