Ethernet 10 / 100 / 1000 Mbit (cat 5, cat 5e and cat 6) network cable wiring and colors pinout

Nowdays ethernet is a most common networking standard for LAN (local area network) communication, officially standardized by IEEE standard 802.3. Nowdays ethernet runs at 10Mb, 100Mb or 1Gb per second. It was originally developed by Xerox Corporation in cooperation with DEC and Intel in 1976. Ethernet uses a bus (old coaxial cable) or star topology (standard UTP cable). Most ethernet networks use unshielded twisted pair (UTP) cable. Category 5 (CAT5) cable widely used, but other variations are available. EIA/TIA specifies RJ-45 connectors - properly called 8P8C - (ISO 8877) for UTP (unshielded twisted pair) cable. (RJ45 refers to a set of connectors beyond the 8P8C standard but the former has replaced the latter in common usage).

1000BASE-T (also known as IEEE 802.3ab) is a standard for gigabit Ethernet over copper wiring. It requires, at least Category 5 cable (the same as 100BASE-TX), but Category 5e (Category 5 enhanced) or Category 6 cable may also be used and are often recommended. 1000BASE-T requires all four pairs to be present and is far less tolerant of poorly installed wiring than 100BASE-TX.

There are two standards for network cable wiring. Both are correct.

EIA/TIA 568A or AT&T 258A Ethernet UTP cable

Pin	Name	Description	EIA/TIA 568B or AT&T 258A cable colors	Name	Pin
1	TX+_D1	Transmit Data+	White with orange stripe	TX+_D1	1
2	TX-_D1	Transmit Data-	Orange with white stripe or solid orange	TX-_D1	2
3	RX+_D2	Receive Data+	White with green stripe	RX+_D2	3
4	BI+_D3	Bi-directional+	Blue with white stripe or solid blue	BI+_D3	4
5	BI-_D3	Bi-directional-	White with blue stripe	BI-_D3	5
6	RX-_D2	Receive Data-	Green with white stripe or solid	RX-_D2	6
7	BI+_D4	Bi-directional+	White with brown strip	BI+_D4	7
8	BI-_D4	Bi-directional-	Brown with white stripe or solid brown	BI-_D4	8

EIA/TIA 568B Ethernet UTP cable

Pin	Name	Description	EIA/TIA 568B cable colors	Name	Pin
1	TX+_D1	Transmit Data+	White with green strip	TX+_D1	1
2	TX-_D1	Transmit Data-	Green with white stripe or solid green	TX-_D1	2
3	RX+_D2	Receive Data+	White with orange stripe	RX+_D2	3
4	BI+_D3	Bi-directional+	Blue with white stripe or solid blue	BI+_D3	4
5	BI-_D3	Bi-directional-	White with blue stripe	BI-_D3	5
6	RX-_D2	Receive Data-	Orange with white stripe or solid orange	RX-_D2	6
7	BI+_D4	Bi-directional+	White with brown strip	BI+_D4	7
8	BI-_D4	Bi-directional-	Brown with white stripe or solid brown	BI-_D4	8

There are three most common Ethernet variants available nowdays:

Length:

Each network segment cable length may be up to 100 meters, although several chip manufacturers claim 150 meters. Autonegotiation is a requirement for using 1000BASE-T, according to the standard. Several device drivers will allow you to force 1000 Mbps full duplex to eliminate autonegotiation issues.

Note:

TX & RX are swapped on Hubs (see crossover cable). Also, please note that it is very important that a single pair be used for pins 1 and 2; 3 and 6, 4 and 5, 7 and 8. If not, performance will degrade.

The + side of each pair is called the tip and the - side is called the ring, a reference to old manual telephone switchboard plugs.

History:

Category 5 cable , commonly known as Cat 5, is an unshielded twisted pair cable type designed for high signal integrity. With the 2001 introduction of the TIA/EIA-568-B standard, the category 5 cabling specification was obsoleted and superseded by the category 5e specification.

The original specification for category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95. These documents specified performance characteristics and test requirements for frequencies of up to 100 MHz. Category 5 cable included four twisted pairs in a single cable jacket. It was most commonly used for 100Mbit/s networks, such as 100BASE-TX Ethernet, although IEEE 802.3ab defined standards for 1000BASE-T - gigabit Ethernet over category 5 cable. Cat 5 cable typically had three twists per inch of each twisted pair of 24 gauge copper wires within the cable. The twisting of the cable reduces electrical interference and crosstalk. Another important characteristic is that the wires are insulated with a plastic (FEP). Special attention also has to be paid to minimizing impedance mismatches at connection points.

Cat 5e cable is an enhanced version of Cat 5 that adds specifications for far-end crosstalk, usually used for gigabit ethernet. Cat 5e cable does not enable longer cable distances for Ethernet networks: horizontal cables are still limited to a maximum of 90 m in length. Cat 5e cable performance characteristics and test methods are defined in TIA/EIA-568-B.2-2001.