Ethernet cables connect computers, routers, modems and peripherals such as printers to networks and Ethernet communications boards. The cables carry signals that allow one to transfer data over a local or wide-area network. Ethernet couplers are plastic or metal connectors that one places between two Ethernets. The coupler allows one to join cables together and make a longer cable. This computer accessory makes it unnecessary for one to open an Ethernet cable and expose the wiring so it can be spliced into a second cable.
A standard Ethernet coupler is a small rectangular box that is open at both ends. The design allows the signal from the cable that one attaches at either end to travel to the cable that one inserts at the opposite side. Inside each open side of the Ethernet coupler are the appropriate wires that match those on the cable.
An Ethernet coupler has colored-coded wires inside the open end of the coupler box. When one properly inserts the end of an Ethernet cable that has connectors covered with a plastic sheath, the cable can make contact with the wires inside the coupler box. A coupler box also has a notch that matches a flexible tab on the sheath of the cable. This notch allows one to secure the cable and prevents inserting the cable incorrectly. To complete the coupling, one inserts the second Ethernet cable into the opposite end of the coupler box.
Before one purchases an Ethernet coupler, it is necessary to determine the type of Ethernet cable with which it will connect. The most common classes of Ethernet cables used by consumers are Cat 5, Cat 5e, Cat 6 and Cat 6a. Each of these cables has a different data transmission rate. These cables normally have their classification printed on their protective exterior sheath.
Cat 6 cables have backward compatibility with Cat 5 cables but, ideally, one should match cable types and couplers when connecting Ethernet cables. Retailers of Ethernet couplers have specifications that match Cat 5 or Cat 6 cables. Using an Ethernet coupler with an incorrect rating can result in data transmission signal loss or failure between the network card and the device to which one attached it.
The maximum length, including any Ethernet coupler used in the configuration, is different for each cable class. The upper limit for Cat 5 cables is 328 feet (100 meters). For Cat 6 cables, the maximum recommended cable length is the same; in mixed network wiring configurations, however, the recommended length drops to 180 feet (55 meters).