3Com 3C250B-TX - SuperStack II Hub 100 User Manual
100BASE-T4 and 100BASE-TX
Fast Ethernet solution for UTP cabling
100BASE-T Fast Ethernet Cabling
Standards Overview
100BASE-T Fast Ethernet is an IEEE
802.3 international standard for Ethernet
at 100Mbps. Fast Ethernet utilizes the
same protocol (CSMA/CD Media Access
Control) as standard 10BASE-T Ethernet.
This high speed performance along with
3 cable type specifications (100BASE-TX,
100BASE-T4, 100BASE-FX) allow
100Mbps connections across most
types of network cabling
100BASE -T4 (see diagram)
The 100BASE-T4 specification defines
100Mbps Ethernet transmission across
Category 3, Category 4, or Category 5
UTP cable at distances up to 100 meters.
100BASE-T4 uses 4 pairs (8 wires) in
the wire bundle.
100BASE-TX (see diagram)
The 100BASE-TX specification defines
100Mbps Ethernet transmission across
Category 5 UTP cable and Type 1 STP
cable at distances up to 100 meters.
100BASE-TX uses 2 pairs (4 wires) in the
wire bundle. Most 100BASE-TX products
support category 5 UTP cabling only.
100BASE-FX (see diagram)
The 100BASE-FX specification defines
100Mbps Ethernet transmission across
62.5/125 micron multimode fiber at
distances up to 412 meters (distances up
to 2 K supported with full duplex 100BASE-
FX). 100BASE-FX uses 2 strands of multi-
mode fiber.
Introduction
As the use of high performance PCs and
servers and high-bandwidth applications
increases, the use of high throughput
networking grows. The most popular method
for high performance PC and server
connections is 100BASE-T Fast Ethernet.
Fast Ethernet provides a high performance
solution at a low cost and simple integration
with 10BASE-T Ethernet.
With broad usage of Fast Ethernet products
has come the need to support a broader
range of network cabling types. Many
buildings contain unshielded twisted pair
(UTP) wiring which was installed many
years ago. While the majority of desktop PC
connections are made with Category 5 UTP
(data grade UTP) cabling, many connections
are made with Category 3 or Category 4
UTP (voice-grade UTP) cabling.
3Com now provides a complete set of
products which support 100Mbps Fast
Ethernet on Category 3, Category 4, or
Category 5 UTP cable.
Applications
CSMA/CD MAC
Management
MII Interface
Customer Choice
Fiber
(100BASE-FX)
Four-Pair
Category 3,4, 5 UTP
(100BASE-T4)
Two-Pair
Category 5 UTP,
STP (100BASE-TX)
Fast Ethernet Physical Layer (PHY) Options