Yesterday I downloaded Wireshark. I've actually used it before once in conjunction with another little program... Anyways the reason I downloaded it was the book recommends it as a packet sniffer. One thing I forgot is you have to set your NIC into promiscuous mode which may require special drivers and running a packet sniffer on the school network may not be the best thing to do. So onto hardware testers.
A wire-map tester is one of the most basic cable testers you can buy. It just checks that the wires in a twisted-pair are in their correct places. It can also check for broken or unconnected wires. Surprisingly this basic tester starts at around 100 dollars.
A protocol analyzes, wait for it, protocols! They come in hardware and software forms. It allows you to troubleshoot problems on a network, doesn't really explain how..., gather traffic info, find unused protocols to remove from your network and traffic generating for penetration testing. And that's that for today.