What is the maximum segment length of a 100Base-FX network?

The Institute of Electrical and Electronics Engineers(IEEE) uses shorthand identifiers like 10Base5, 10BaseF, 100BaseFX, etc which include information about the transferring speed , the physical medium used for transferring, segment length (the length of the wire that can be used for transferring before attenuation happens), etc. In this blog, we will see how the nomenclature is done and then find out the maximum segment length of 100BaseFX. So, let's get started.

What are pieces of information hidden in the name itself or how is the nomenclature done?

  1. Starting number: Suppose you have a network of 10BaseT , the number 10 , which is present at the starting of the identifier represents the standard transmission speed of 10 megabits per second i.e. 10Mbps .
  2. The word Base: It refers to Base band digital transmission. This tells that the network uses only one carrier frequency for signaling and requires all the network stations to share its use.
  3. Segment Type Or Segment length: This last part of the identifier can be a digit or a letter .
  • Digit: This tells the segment length (in meters) or how long it can be the segment of the cable before any attenuation happens. In 10Base5, the maximum segment length can be 500 meters.
  • Letter: This letter identifies the segment type or physical type of cable. In 10BaseT , the segment type is T wisted-pair cable. In 10BaseF , the segment type is F iber.
The last character (‘X’, etc) refers to the line code method used. Line code is a pattern of voltage, current or photons used to represent the digital data transmitted on the transmission line. Fast Ethernet cable is sometimes referred to as 100BaseX where X can be replaced by two variants i.e. FX and TX.


100BaseFX is the Fast Ethernet Cable over the Optical Fiber . 100 in the 100BaseFX refers that the data transfer rate is 100 megabits per second i.e. 100Mbps . The word Base refers to Baseband digital transmission. The letter F signifies that the segment type is Optical Fiber .

The maximum segment length is 2000 meters.
  1. It has two pairs of optical fibers. The first transmit frames from hub to device and the second transmits from device to hub.
  2. In most of the Fast Ethernet applications, the individual devices are connected by twisted-pair copper wires i.e. 100BaseTX (maximum segment length is only 100 meters) and the optical fibers are used for transmission over longer distances (as maximum segment length is 2000 meters of 100baseFX). So, 100baseTX to 100Base FX convertor is required for sending the signal from the sender end over the optical fiber. Similarly, at the receiver end, 100baseFX to 100Base TX is required.

This was all about 100BaseFX and its maximum segment length. Hope you learned something new today.

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