Ok. Two things here:



First, don't plug this into any network that you don't personally control without permission. That kind of splice is extremely susceptible to interference, potentially causing packet corruption, which can screw up not only your connection, but possibly those of other people on the network. Modern equipment is better at filtering out bad packets than the older stuff, but it can still cause unpredictable issues that are hard to track down. If you use one of these in your dorm room don't be surprised if you suddenly find that your network connection has been shut off. Also don't be surprised if your network throughput goes to heck since interference will mangle your packets and they may have to be resent several times.



Second, the length limit for wired ethernet connections is 100m. (64 byte-times multiplied by the speed of electricity through copper.) This includes any cable that may be in the wall between you and the network switch. Attaching a long cable that puts the total length over this distance will cause what are called "late collisions" which can potentially bring down large segments of the network and are very difficult to track down.



Your best bet is usually to go down to the nearest Home Depot equivalent where they sell bulk communications cable and get whatever length you need along with a crimper and a box of plugs. You can probably earn enough making custom-length cords for your friends to pay for the tools.



Your second-best bet is to get one of the splice connectors that let you plug a cable into each end and just hook your two cables together. The connectors usually cost less than a dollar.



If you find you _must_ splice a cable in this manner, keep the amount you untwist it as short as possible (about a centimetre if you're dexterous) and solder the wires together, preferably without twisting them around each other. Then polish the solder joints to assure that there are no sharp points which will emit and pick up interference. Then coat each joint individually with fingernail polish and wrap it in electrical tape. Then borrow a cable tester and see how good a job you did. If it meets Cat3 standards, then it will handle 10MB/s. Cat5 will handle 100MB/s. Higher than that should be capable of gigabit. Set the speed of your network card accordingly.