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White with Orange
Brown with White
Orange with White
White with Brown
White with Green
Green with White
Blue with White
White with Blue
RJ45 Connector Specifications
- 8P8C RJ-45 Connector (8-pin connector)
- Through Hole PCB mount socket
- Compatible with all CAT and UDP cable
CAT Cables, USART modules, RS232 to TTL converters, RJ45 Modules
Other RJ45 Connector
Molex RJ45 Connector, RJ45 MagJack Breakout, Transceiver Board
Where to Use RJ45 Connectors
RJ45 is a type of communication protocol that is used for Ethernet and other long distance communications. In this type of communication, Data is transmitted between two electronics devices like Microcontrollers or Microprocessors over a very long distance without getting it lost. Normally communication protocols like SPI, USART, IIC will be used to transfer these data. These two devices are linked using a cable like CAT cables. The CAT cables are connected to the circuit through this RJ45 Connector. These connectors support any type of Ethernet cable like USP, CAT5e, CAT6 etc..
There are also many types of RJ45 connectors, but they all serve the same function other than the appearance and built quality. So if you are looking for a connector to communicate through RJ45 Protocol then this connector might be the right choice for you.
How to use RJ45 Connector
The RJ45 connector has 8 pins as shown above. It is very important to select the appropriate pins for your data and ground to make the RJ45 protocol work efficiently. The main advantage of using RJ45 communication is that they are connected using CAT cables. These CAT cables are made up of twisted paired wires and the wires are housed inside a cable which can protect it from external noise. Since the wires are twisted in a pair of two, among these two wires one will be used to carry the signal or the data and the other will be a ground wire which will remove the noise from the data wire during high distance transmission.
A simple sample connection diagram for a USART connection with two RX and TX data lines is shown below
The data lines can be anything from USART, SPI or even IIC. Note that in every twisted pair one wire carries the data and the other is connected to ground. Other alternative methods for this protocol are the RS232 communication and the RS485 Communication protocol. These cables also support POE (Power over Ethernet) and hence can also carry power to the modules if required
- Commonly used in Ethernet Connection
- Transmit Data over Long distance
- Transmit data in noisy environment
- Long distance wired Connection
- Supports Power over Ethernet
Dimensions of the module
RJ45 8-Pin Connector Datasheet
The way the RJ45 connector is wired to Cat 5, 5e, and 6 cables differs depending upon the type of cable required. To understand why, it’s necessary to understand how computers communicate with the network.
RJ45 modular connectors, also known as 8P8C connectors, are used to connect computers to local area networks. The way the RJ45 connector is wired to Cat 5, 5e, and 6 cables differs depending upon the type of cable required. There are straight-through cables, crossover cables, and rollover cables. To understand why, it’s necessary to understand how computers communicate with the network.
PC Communication Standards
When looking at an RJ45 connector from its underside, the first pin is on the left-hand side and is called pin number 1. Computers use pins 1 and 2 to send information and pins 3 and 6 to receive information.
In order to simplify wiring, upstream devices (including switches, hubs, and routers) use pins 3 and 6 to send and pins 1 and 2 to receive information so that a PC and hub can communicate using a cable that has an identical RJ45 pinout at either end.
This is known as the medium dependent interface (MDI) configuration.
The telecommunications industry has two standards for cable RJ45 pinouts, T568A and T568B. These standards determine how each of the four pairs of colored wires is connected on the RJ45 connector:
- The four colors used on Cat 5 and 6 cables are green, orange, blue, and brown. One wire in each pair has a solid color and the other has a white stripe added.
- On T586A cables, pin 1 is white-green and pin 2 green, whereas on T586B cables, pin 1 is white-orange and pin 2 orange.
- The difference continues in that pins 3 and 6 are used for the other color. With both standards, the blue pair is always on pins 4 and 5 and the brown pair on pins 7 and 8.
T586B is the most common, although the government often uses T586A. The choice is irrelevant provided all components follow the same standard.
The wiring of both ends of straight-through cables is the same, and these are used to connect computers to upstream devices such as a router or hub that uses the MDI communication protocol.
A crossover cable is different in that the wiring connection at one end is to the T586A configuration and on the other the T586B configuration. This means that two similar devices can communicate with each other, so this is how to connect two computers or two switches or hubs to each other. This type of connection is known as a medium dependent interface crossover (MDI-X).
A rollover cable is one where the pinouts are reversed. Pin 1 becomes pin 8 and pin 2 becomes pin 7. This type of cable is not used in computer networks, except in very special applications.
One use is as a console cable used to configure Cisco switches and other Cisco equipment. It is never used for a network connection.
Selecting the Right Network Cable
When working on a network, it’s essential to use the same cabling standard throughout.
It is relatively easy to identify which standard is in use because:
- The orange pair is always on the left-hand side of T586B cables.
- The green pair is on the left-hand side of the less common T586A configuration.
Another way of identifying the right RJ45 pinout is to use a network cable tester.
When connecting unlike pieces of equipment, always use a straight-through cable. But if connecting two similar pieces of equipment, use a crossover cable or a crossover module. Additionally, some equipment is able to recognize when a crossover cable is needed and automatically switches the pin configuration internally so a straight-through cable can be used.
This article was contributed by Ron Vogel of T3 Innovation.
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