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Chapter 1
Introduction
Overview
Ethernet Switching Technology
Key Product Features
Package Contents
Installation Guide
Overview
The EIS-408FX-M and EIS-408FX-S are web-managed, industrial Ethernet rail switches that
have six 10/100MBaseTX ports, plus two 100BaseFX ports (multi-mode “-M” or single-mode “-S”
models), and are designed to operate under harsh environmental conditions. These switch
models also include advanced support for media redundancy and offer communication fail-over
times less than 300 milliseconds. These switch models also have a wide operating ambient
range and include redundant power inputs with reverse polarity protection. The unit includes a
DC-IN jack and may be optionally powered from an AC-DC wall transformer for Small
Office/Home Office (SOHO) applications. It is packaged in a rugged, IP-30 aluminum enclosure
for increased protection from extreme temperature, vibration, dust, and debris. This switch has
also passed several safety certifications to help ensure safe and reliable data transmission for
industrial applications.
In addition to supporting the Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol
(RSTP), this switch includes a proprietary redundant ring technology that allows it to manage a
media loop with other switches of the same type. A media loop is created when a message sent
out on one port is received by the same switch at another port (two message paths exist). This
switch is smart enough to temporarily disable the second path, holding it as a backup in case the
primary path fails. It also includes a normally closed alarm relay to signal a port failure (if
enabled). The switch will automatically fail-over to a secondary path within 300ms if the primary
path is lost.
These switches also support SC-type fiber connections in both single-mode and multi-mode
versions, useful for extending transmission distance. A web-based management interface
ensures easy operation and reconfiguration via a standard internet web browser.
Ethernet Switching Technology
To better understand the operation of an Ethernet switch, we need to first differentiate it from a
hub. An Ethernet hub (or repeater) is a device that is used to simply connect Ethernet nodes.
Any message at one hub port is repeated on all ports. That is, hubs forward data packets they
receive from a single station to all hub ports. As a result, all port devices connected to a single
hub will share the same bandwidth. Then as nodes are added to the network hub, they compete
for this finite amount of bandwidth and this can cause data collisions to occur, making network
determinism impossible to attain, especially on busy networks. Now determinism is a term that is
used to describe the ability to guaranty that a packet is sent or received in a finite and predictable
amount of time. The inherent lack of determinism is the main reason that traditional Ethernet had
problems being accepted for use in critical control applications, as most control systems have a
defined time requirement for packet transmission, typically less than 100ms.
