How to Connect a Network Cable
Before Wi-Fi became ubiquitous, networking was all about running cables. One reason Ethernet became so popular was because it carried with it a standardized infrastructure that made it easy to wire different network elements together.
What is RJ45, Anyway?
RJ stands for registered jack and refers to a series of standard interface connectors from Bell for telecommunications. The ethernet RJ45 jack for networking is physically very similar to the RJ11 for public switched telephones but it is larger and the two are not interchangeable. While you cannot plug a network cable into a phone jack, attempting the reverse is worse, as the power carrying down the phone line could damage your network card.
- RJ45: This Ethernet connector has eight connections and carries eight conductors in either a straight-through or crossover configuration. Straight-through was for connecting computers to hubs and other network hardware, while crossover was for connecting two network adapters; although auto-sensing adapters have made crossover cable largely unnecessary.
- RJ11: Similar but smaller, RJ11 has six connectors but only uses four wires, leaving the outer pair unused. Each RJ11 can connect two phone lines using unshielded twisted pairs.
What About Network Cards?
Every network adapter helps a computer connect to a LAN and through there to other computers. Companies like Intel make a wide range of adapters for everything from Fast to Gigabit Ethernet, all of which are compatible with cat five cable. While the RJ45 connectors for the network cable may all be the same, the same cannot be said of how the network interface card connects to the computer, which has three options:
- USB: USB adapters are the easiest to install, you just connect them to any handy USB port. The side effect is that all data has to go through the USB controller as well as the adapter, and that if the host controller goes to sleep you lose connectivity.
- PCI: This is a legacy parallel bus where all devices share 133 MB/sec of bandwidth. Commonly found on legacy devices it can struggle under the demands of Gigabit Ethernet.
- PCI Express: This serial technology gives Intel Gigabit network adapters the internal bandwidth to take full advantage of high speed connections. Each lane offers more bandwidth than the entire PCI bus, and it's all dedicated to a single PCI Express device with no sharing involved.
Setting Up a Network
While the hardware may be standardized, the real trick in networking is running the cables to connect various network components. Cat 5 cable benefits from shorter runs wherever possible, and it's also important to keep the hardware out of the way when running RJ45 cable from one component to another.