Managing a network requires adaptability. Your network is rarely going to remain static after the initial design is implemented. New users or equipment will be added, and before you know it you will need more connections in the office. Ethernet splitters are a good way to add connections without rewiring the whole place, and those extra connections can come in handy for purposes other than new users.
Ethernet splitters come in different flavors and for different purposes. At the low end, Ethernet splitters are Y-connectors that connect two Cat5 cables to a single LAN connection. They work in pairs with a second Y splitter then connected to a hub to create an additional connection. The system uses the additional wire connections in Ethernet connections that aren't used in standard connections. This system is particularly useful when you need an extra connection but the cost for pulling cable is prohibitive. You can find these parts online for around $10 (see X-treme Geek for an example).
More substantial is the full duplex fast Ethernet Tap Splitter that NetOptics sells. The FX-Tap to TX Full Duplex Tap Splitter can be invaluable for monitoring and managing IP traffic to a specific device. One IP connection goes to the device, while the second IP connection connects to a Sniffer or network analyzer. This device was designed so that it wouldn't impact on the throughput of traffic through the splitter, and if power fails traffic continues to flow unaffected. Since you can remove the detection device without affecting the actual connection, this device lets you plug in different diagnostic equipment without having to disrupt communications.
Barrie Sosinsky is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.