100BASE-TX — Fast Ethernet

What is 100BASE-TX?
100BASE-TX
100BASE-TX is the most common Fast Ethernet physical layer, transmitting data through two twisted wire-pairs (one for each direction), which provide full duplex operation with 100 Mbit/s of throughput in each direction.
The cabling distance is limited to 100 metres (328 ft) for each network segment.
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Fast Ethernet was introduced in 1995 as the IEEE 802.3u standard
- 100BASE-TX is part of the 100BASE‑T family, comprising several Fast Ethernet standards for twisted pair cables.
- 100BASE‑T devices are generally backward compatible with existing 10BASE‑T systems, enabling simple retrofits and plug-and-play upgrades from 10BASE‑T.
Ethernet vs RS-232 vs RS-422 vs RS-485
It is important not to confuse communication protocols with standards for electrical characteristics of physical communication media. Different communication media are used depending on project needs. The standards’ main differences are the communication speeds, the maximum number of connected devices and the physical distance between connected nodes.
RS-232
The RS-232 (Recommended Standard 232) or also known EIA-232 (Electronic Industries Alliance-232) standard is used only in point-to-point communications, i.e. it only supports communications between two devices, which in the case of the Modbus protocol would be a master and a slave device. The maximum speed of RS-232 is around 115Kbp/s with a maximum distance between network devices of about 30m.
RS-422, or also TIA/EIA-422, was intended to replace the older RS-232C standard with a standard that used differential signalling to provide higher speeds, longer cable lengths and less noise. At short distances, data transmission rates can reach up to 10 Mbit/s. At lower rates, data can be send through cables with a length of up to 1,500 meters.
RS-485
The RS-485 (Recommendad Standard-485) or EIA-485 (Electronic Industries Alliance-485) standard is one of the most widely used standards for serial communication in industrial applications. The main difference with RS-232 is that it allows more than two devices on the network, enabling to have several slaves. It achieves rates of up to 12Mbps and in rarer cases up to 50Mbps, while the maximum distance within the network is 1200m, and the maximum number of devices on the network is 32.
Ethernet
Depending on the variation used, transimission speeds with Ethernet range from 100Mbps and up to 10Gbps, while maximum distance can vary from 100m to 200m depending on project conditions and the type of cable used. In some cases, it is possible to use fiber optic networks, which enable longer distances and higher communication rates, as well as wireless communication.
Tags: Ethernet, gateway, Grid Automation, IEC 61850, IED, Protection Relay, Relays, RS-232, RS-422, RS-485, RTU, serial

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Communication Interfaces
- RS-232 — TIA/EIA-232
- RS-485 — TIA/EIA-485
- RS-422 — TIA/EIA-422
- 100BASE-FX Ethernet
- 100BASE-TX Ethernet
The RS-232 (Recommended Standard-232) or also known EIA-232 (Electronic Industries Alliance-232) is a standard for the serial transmission of data in industrial applications.
The standard defines the timing, electrical characteristics and meaning of signals as well as the physical size and pinout of connectors.
The RS-485 (Recommended Standard-485) or also known EIA-485 (Electronic Industries Alliance-485) standard defines the characteristics of an electrical interface for serial communications in industrial control systems.
In contrast to the older RS-232, it allows to balance electrical signals and connect multiple device to the network, which can stretch over longer distances and harsher environments.
The RS-422 (Recommended Standard-422) or also known EIA-422 (Electronic Industries Alliance-422) standard defines the characteristics of an electrical interface for serial communications in industrial control systems.
It was designed to replace the older RS-232C standard in order to provide higher speed (up to 10 Mb/s), better immunity from noise, and longer cable lengths (up to 1,500 meters).
100BASE-FX is a physical layer specification for Fast Ethernet over fiber optics using two multi-mode fiber optic strands for both links, reception and transmission.
The maximum length is 412 meters for half-duplex connections (to ensure that collisions are detected) or 2 kilometers for full-duplex.
100BASE-TX is the most common Fast Ethernet physical layer, transmitting data through two twisted wire-pairs (one for each direction), which provide full duplex operation with 100 Mbit/s of throughput in each direction.
Cabling distances are limited to 100 metres (328 ft) for each network segment.
1ooBASE-TX & iGrid
All iGrid devices can be ordered with different configurations of Ethernet and serial ports, including RS-232, RS-422, RS-485 and Ethernet (100BASE-TX/FX) amongst others. We have experience with all kinds of protocol conversions from and to both serial and Ethernet/TCP protocols and networks.

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