Crossover cable suitable for use with 100BASE-T4 (please note : Gigabit crossover) Fast Ethernet

8P8C modular crossover adapter

An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices together directly where they would normally be connected via a network switch, hub or router. For example, one would use a crossover cable to directly connect two personal computers via their network adapters. Image File history File links Download high resolution version (2397x1944, 1482 KB) Public domain, I took this photo myself, ocrho. ... Image File history File links Download high resolution version (2397x1944, 1482 KB) Public domain, I took this photo myself, ocrho. ... In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s, against the original Ethernet speed of 10 Mbit/s. ... Image File history File linksMetadata Download high resolution version (2592x1944, 1613 KB) A Crossover Adapter, by Fibrionic (a brand of german mail order firm Pearl). ... Image File history File linksMetadata Download high resolution version (2592x1944, 1613 KB) A Crossover Adapter, by Fibrionic (a brand of german mail order firm Pearl). ... An 8P8C modular plug before having been crimped onto a cable Connector and cable The 8 Position 8 Contact (8P8C) modular plugs and jacks are communications connectors. ... A Crossover Cable suitable for use with 100baseT4. ... A network switch is a computer networking device that connects network segments. ... In general, a hub is a centre point: a wheels hub, which is the center of the wheel with spokes radiating out from it. ... This article is about a computer networking device. ... This article or section is in need of attention from an expert on the subject. ...

Overview

The 10BASE-T and 100BASE-TX Ethernet standards use one wire pair for transmission in each direction. The Tx+ line from each device connects to the tip conductor and the Tx- line is connected to the ring. This requires that the transmit pair of each device be connected to the receive pair of the device on the other end. When a terminal device is connected to a switch or hub, this crossover is done internally in the switch or hub. A standard straight through cable is used for this purpose where each pin of the connector on one end is connected to the corresponding pin on the other connector. 10BASE-T cable 10BASE-T plug 10BASE-T is an implementation of Ethernet which allows stations to be attached via twisted pair cable. ... In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s, against the original Ethernet speed of 10 Mbit/s. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... In the context of telecommunications, a terminal is a device which is capable of communicating over a line. ... A network switch is a computer networking device that connects network segments. ... In general, a hub is a centre point: a wheels hub, which is the center of the wheel with spokes radiating out from it. ...

One terminal device may be connected directly to another without the use of a switch or hub, but in that case the crossover must be done externally in the cable. Since 10BASE-T and 100BASE-TX use pairs 2 and 3, these two pairs must be swapped in the cable. This is a crossover cable. A crossover cable must also be used to connect two internally crossed devices (e.g., two hubs) as the internal crossovers cancel each other out. This can also be accomplished by using a straight through cable in series with a modular crossover adapter.

Because the only difference between the TIA/EIA-568-A and T568B pin/pair assignments are that pairs 2 and 3 are swapped, a crossover cable may be envisioned as a cable with one connector following T568A and the other T568B. Such a cable will work for 10BASE-T or 100BASE-TX. 1000BASE-T4 (Gigabit crossover) which uses all four pairs requires the other two pairs (1 and 4) to be swapped and also requires the solid/striped within each of those two pairs to be swapped. TIA/EIA-568-B is a set of three telecommunications standards from the Telecommunications Industry Association, a 1988 offshoot of the EIA. The standards address commercial building cabling for telecom products and services. ... An electrical connector is a conductive device for joining electrical circuits together. ... Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802. ...

Crossover cable pinouts

Two pairs crossed, two pairs uncrossed
10baseT/100baseTX crossover ( shown as T568A )

Pin	Connection 1 pair	Connection 2 pair	Connection 1	Connection 2	Pins on plug face (jack is reversed)
1	3	2	white/green stripe	white/orange stripe
2	3	2	green solid	orange solid
3	2	3	white/orange stripe	white/green stripe
4	1	1	blue solid	blue solid
5	1	1	white/blue stripe	white/blue stripe
6	2	3	orange solid	green solid
7	4	4	white/brown stripe	white/brown stripe
8	4	4	brown solid	brown solid

Certain equipment or installations, including those in which phone and/or power are mixed with data in the same cable, may require that the "non-data" pairs 1 and 4 (pins 4, 5, 7 and 8) remain un-crossed. Image File history File links Wire_white_green_stripe. ... Image File history File links Wire_white_orange_stripe. ... Image File history File links Rj45plug-8p8c. ... Image File history File links Wire_green. ... Image File history File links Wire_orange. ... Image File history File links Wire_white_orange_stripe. ... Image File history File links Wire_white_green_stripe. ... Image File history File links Wire_blue. ... Image File history File links Wire_blue. ... Image File history File links Wire_white_blue_stripe. ... Image File history File links Wire_white_blue_stripe. ... Image File history File links Wire_orange. ... Image File history File links Wire_green. ... Image File history File links Wire_white_brown_stripe. ... Image File history File links Wire_white_brown_stripe. ... Image File history File links Wire_brown. ... Image File history File links Wire_brown. ...

Gigabit crossover
All four pairs crossed
10base-T/100base-TX/1000base-TX/T4 crossover (shown as T568B)

Pin	Connection 1 pair	Connection 2 pair	Connection 1	Connection 2	Pins on plug face (jack is reversed)
1	2	3	white/orange stripe	white/green stripe
2	2	3	orange solid	green solid
3	3	2	white/green stripe	white/orange stripe
4	1	4	blue solid	white/brown stripe
5	1	4	white/blue stripe	brown solid
6	3	2	green solid	orange solid
7	4	1	white/brown stripe	blue solid
8	4	1	brown solid	white/blue stripe

In practice, it does not matter if your Ethernet cables are wired as T568A or T568B, just so long as both ends follow the same wiring format. It is just as valid to make a four-pair crossover using T568A, or a two pair crossover using T568B, as it is to wire them the way shown here. Typical commercially available "pre-wired" cables can follow either format depending on who made them. What this means is that you may discover that one manufacturer's cables are wired one way and another's the other way, yet both are "correct" and will work. In either case, T568A or T568B, a normal (un-crossed) cable will have both ends wired according to the layout in the first connections column. Image File history File links Wire_white_orange_stripe. ... Image File history File links Wire_white_green_stripe. ... Image File history File links Rj45plug-8p8c. ... Image File history File links Wire_orange. ... Image File history File links Wire_green. ... Image File history File links Wire_white_green_stripe. ... Image File history File links Wire_white_orange_stripe. ... Image File history File links Wire_blue. ... Image File history File links Wire_white_brown_stripe. ... Image File history File links Wire_white_blue_stripe. ... Image File history File links Wire_brown. ... Image File history File links Wire_green. ... Image File history File links Wire_orange. ... Image File history File links Wire_white_brown_stripe. ... Image File history File links Wire_blue. ... Image File history File links Wire_brown. ... Image File history File links Wire_white_blue_stripe. ...

Other networking technologies

Other technologies use different pairs to transmit data, so crossover cables for them have different configurations to swap the transmit and receive pairs:

• Twisted pair Token ring uses T568B pairs 1 and 3 (the same as T568A pairs 1 and 2), so a crossover cable to connect two Token Ring interfaces must swap these pairs, connecting pins 4, 5, 3, and 6 to 3, 6, 4, and 5 respectively.
• A T1 cable uses T568B pairs 1 and 2, so to connect two T1 CSU/DSU devices back-to-back requires a crossover cable that swaps these pairs. Specifically, pins 1, 2, 4, and 5 are connected to 4, 5, 1, and 2 respectively.
• A 56K DDS cable uses T568B pairs 02 and 04, so a crossover cable for these devices swaps those pairs (pins 01, 02, 07, and 08 are connected to 07, 08, 01, and 02 respectively).

Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... For the guitar distortion pedal, see BOSS DS-1. ...

Automatic crossover

Automatic MDI/MDI-X Configuration is specified as an optional feature in the 1000BASE-T standard^[1], meaning that straight-through cables will usually work between Gigabit capable interfaces. This feature eliminates the need for crossover cables, obsoletes the uplink/normal ports and manual selector switches found on many older hubs and switches, greatly reducing installation errors. Note that although Automatic MDI/MDI-X is generally implemented, a crossover cable would still be required in the occasional situation that neither of the connected devices has the feature implemented and enabled.

Even for legacy 10/100 devices, many NICs, switches and hubs automatically apply an internal crossover when necessary. Besides the eventually agreed upon Automatic MDI/MDI-X, this feature may also be referred to by various vendor-specific terms including: Auto uplink and trade, Universal Cable Recognition and Auto Sensing.

Networks created using crossover cables

A two-computer network, sometimes called a peer-to-peer network, can be created using a crossover Ethernet cable. As in any other TCP/IP network, each computer needs to be assigned a unique IP address. In this network configuration, a default gateway is not used and can be unspecified. A peer-to-peer (or P2P) computer network is a network that relies on the computing power and bandwidth of the participants in the network rather than concentrating it in a relatively few servers. ... An IP address (Internet Protocol address) is a unique address that certain electronic devices currently use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ... A default gateway is a node on a computer network that serves as an access point to another network. ...

Information on how to deploy such network can be found here An IP address (Internet Protocol address) is a unique address that certain electronic devices currently use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ... A graphic representation of relationships and source of the various variables representing a chunk of C subnets In computer networks, a subnetwork or subnet is a range of logical addresses within the address space that is assigned to an organization. ...

See also

• Registered jack which expands on the introduction and evolution of these connectors.

A registered jack (RJ) is a standardized physical interface for connecting telecommunications equipment (commonly, a telephone jack) or computer networking equipment. ...

References