This is primarily used in telephone wiring.Ĭategory 4 specifies cables and connectors that supports up to 20MHz and data rates up to 16Mbps. Category Rating System specifies the definition of performance categories for 100 ohm UTP cabling system.Ĭategory 3 specifies the twisted pair cable and connecting hardware that can support transmission frequency up to 16MHz, and data rates up to 10Mbps. RJ-11 is a 6-position, 4-conductor jack used in telephone wiring, and RJ-45 is a 8-position, 8-conductor jack used in 10BaseT and 100BaseT ethernet wiring.Įlectronic Industries Association (EIA) developed the TIA/EIA-568-A standard, which specifies wiring and performance standards for Unshielded Twisted Pair (UTP) cabling.

These are used in telephone and data jack wiring registered with FCC. It is preferable to wire to T-568B standards if there is no pre-existing pattern used within a building. The difference between the two is the position of the orange and green wire pairs. T-568A and T-568B are the two wiring standards for RJ-45 connector data cable specified by TIA/EIA-568-A wiring standards document. What are T-568A and T-568B wiring standards, and how are they different? There are pin number designations for each color in T-568B and T-568A.ĥ Blue Stripe Not Used Blue Stripe Not Usedħ Brown Stripe Not Used Brown Stripe Not Used Straight-through cables are used to connect a computer to an ethernet switch, or a router to an ethernet switch. Most ethernet switches today provide an uplink port, which prevents a use of cross-over cable to daisy chain another ethernet switch.

Cross-over cable is also used to connect a router to a computer, or ethernet switch (hub) to another ethernet switch without an uplink. To network two computers without a hub, a cross-over cable is used. The unused pins are generally connected straight-through in both straight-through and cross-over cables. Cross-over cables are used to connect TX+ to RX+, and TX- to RX-, which connects pin 1 to pin 3, pin 2 to pin 6, pin 3 to pin 1 and pin 6 to pin 2. Straight-through cable, as its name suggests, connects pin 1 to pin 1, pin 2 to pin 2, pin 3 to pin 3, and pin 6 to pin 6. Pins 4, 5 (Blue) and 7, 8 (Brown) are NOT used. As noted above, the RJ45 cable uses only 2-pairs of wires: Orange (pins 1 & 2) and Green (pins 3 & 6). The RJ45 data cables we use to connect computers to a Ethernet switch is straight-through cables. More on straight-through and cross-over connections The DTE equipment terminates the signal, while DCE equipment do not.

The cross-over cables are used when connecting DTE to DTE, or DCE to DCE equipment such as computer to computer, computer to router or gateway to hub connections. The straight-through cables are used when connecting Data Terminating Equipment (DTE) to Data Communications Equipment (DCE), such as computers and routers to modems (gateways) or hubs (Ethernet Switches). To create a cross-over cable, you'll wire T-568A on one end and T-568B on the other end of the cable. The diagram depicted on the left and right shows clip of the RJ-45 connector down. To create a straight-through cable, you'll have to use either T-568A or T-568B on both ends of the cable.

Color code for ethernet connector