Step 4: Cut the wires as straight as possible, about 0.5 inch above the end of the jacket. Be sure not to untwist them any farther down the cable than where the jacket begins we want to leave as much of the cable twisted as possible.

Step 3: Untwist the wire pairs and neatly align them in the T568B orientation. Cat 6 cables have a spine that will also need to be cut. For Cat 5e, you can use the pull string to strip the jacket farther down if you need to, then cut the pull string. Step 2: Spread the four pairs of twisted wire apart. Step 1: Strip the cable jacket about 1.5 inch down from the end. The tables below show the proper orientation of the colored wires to the pins. T568B is the most common and is what we'll be using for our straight Ethernet cable. The two standards for wiring Ethernet cables are T568A and T568B. Each pin is identified by a number, starting from left to right, with the clip facing away from you. There are four pairs of wires in an Ethernet cable, and an Ethernet connector (8P8C) has eight pin slots. Cable tester (optional, but recommended).Modular connector (8P8C plug, aka RJ45).Unshielded twisted pair (UTP) patch cable.

All other pins are for modem control signal tests and are not necessary to connect unless you wish to test those signals.ĭB-9 RS-422, RS-485 Loopback Connection (Sealevel Product Specific)ĭB-25 RS-232 Loopback Connection (EIA-232)ĭB-25 RS-422, RS-485, RS-530 Loopback ConnectionSure, you can buy Ethernet cables from the store, but where's the fun in that? If you want to make custom cable lengths or crossover cables, or repair a broken connector, why not do it yourself? Here's how.īefore you get started, make sure you have the necessary tools, and decide whether you're going to use Cat 5e or Cat 6 network cables.

Pins marked in red are the data lines, Tx and Rx, and are necessary for the loopback and BERT testing. Use the diagram appropriate to your electrical interface.ĭB-9 RS-232 Loopback Connection (TIA-574) If you want to test modem control signals or you need to construct your own loopback, follow the instructions below. Please contact your sales representative for more information. Item number LB102 is a DB-25 loopback that is used to test RS-232 serial ports. Item number LB101 is a DB-9 loopback that is specially constructed to test data signals on RS-232 and Sealevel RS-422, RS-485 serial ports. Additional loopback plugs can be purchased for a small charge. Sealevel serial I/O devices typically include a loopback plug with each shipment that can be used to test data lines.

How to make a ethernet loopback cable