Lantronix Switch LFH4 M User Manual

LFH4-M/LFH8-M  
Mini Fast Hubs  
Installation Guide  
 
CHAPTER 1 Introduction  
1.1 Product Introduction  
Congratulations on your purchase of the LFH 4-port or 8-port Mini Fast  
Ethernet Hub! The LFH4-M and LFH8-M are designed to give you the  
ultimate in flexibility, ease-of-use, and reliability.  
The LFH4-M and LFH8-M Mini Fast Ethernet Hubs are 100BASE-TX  
multiport Class II repeaters for use with networks using Unshielded  
Twisted Pair (UTP) category 5 cable or Shielded Twisted Pair (STP)  
cable. The LFH hubs are simple to install, and Link/Activity, Partition,  
and Collision LEDs provide convenient monitoring of the status of the  
hub and of each port. For additional expansion, the hub offers an  
Uplink port that makes it easy to cascade the hub to another Fast  
Ethernet hub.  
The LFH4-M/LFR8-M hubs can be placed on a tabletop or wall-  
mounted, and provide the ideal solution for small to medium  
100BASE-TX Fast Ethernet networks. The LFH hubs are designed  
to comply with the IEEE 802.3u Fast Ethernet standard.  
To insure network reliability, the LFH4-M and LFH8-M monitor each  
port for signal quality and automatically disconnect stations transmit-  
ting noise, reconnecting them when the problem is resolved. Data  
packets that exceed the maximum legal length for IEEE802.3 Ethernet  
packets are automatically truncated. This prevents a device from  
blocking the network by transmitting a continuous data stream or  
excessively long packet. The LFH hubs completely retime and restore  
full-amplitude waveforms for each retransmitted packet. A full-length  
preamble is also generated, insuring packet integrity across the  
network.  
2
 
1.2 Features  
The LFH4-M provides four 100BASE-TX ports and the LFH8-M  
provides eight 100BASE-TX ports for Fast Ethernet connectivity  
The LFH4-M/LFH8-M comply with the IEEE 802.3u Fast Ethernet  
standard  
Supports Category 5 Unshielded Twisted Pair (UTP) or Shielded  
Twisted Pair (STP) cable  
An Uplink port on the front panel enables the LFH4-M/LFH8-M to  
be connected to another 100BASE-TX hub using a straight-through  
cable  
Performs preamble regeneration, signal retiming and restoration,  
extension of fragmented packets, automatic partitioning, and jabber  
truncation  
Global Power and Collision LEDs and individual Partition and  
Link/Activity LEDs indicate system status  
Comes with external AC/DC power supply (120VAC or 220VAC)  
FCC Class A, CE, UL, CUL, TUV certifications  
Five year limited warranty  
3
 
1.3 Product Specifications  
Standards  
IEEE 803.3u 100BASE-TX Ethernet  
Network Media 100BASE-TX Unshielded Twisted Pair cabling  
(Category 5 UTP)  
Max. Lengths  
100 meter hub-to-station connection  
5 meter hub-to-hub connection  
Connectors  
8/16 RJ45 connectors, one crossover ÒUplinkÓ port  
LED indicators Power, Collision, Partition, Link/Activity  
Dimensions  
221mm x 111mm x 26mm (L x W x H)  
Environment  
Temperature: Operating: 0¡C to 40¡C  
Storage: -20¡C to 70¡C  
Humidity  
Operating: 10 to 80%RH  
Storage: 5 to 90%RH  
Certifications  
Warranty  
FCC Class A, CE, UL, CUL, TUV  
5-year limited  
4
 
Chapter 2 Using the LFH Hub  
2.1 Packing Checklist  
Your LFH package should contain the following:  
An LFH4-M or LFH8-M Mini Fast Hub  
Mounting brackets and screws  
External AC/DC power adapter (120VAC or 220VAC)  
Installation Guide  
If any of these items are missing, contact your dealer immediately.  
2.2 Planning 100BASE-TX Networks  
100BASE-TX networks need to be planned out slightly differently from  
10BASE-T networks, because new hubs and new wiring configurations  
are necessary. (10BASE-T hubs are incapable of sending or receiving data  
at 100Mbps, so a 100BASE-TX network requires a 100BASE-TX hub.)  
100BASE-TX supports a maximum length of 100 meters from a network  
station to a hub. The total network diameter (the maximum cable  
distance between any two stations on the network) is 205 meters for  
100BASE-TX, as opposed to 500 meters for 10Mbps Ethernet. Because  
100BASE-TX sends signals ten times faster than 10BASE-T, the collision  
window (the time during which the network can detect a collision  
between packets) is reduced to one-tenth the duration of the 10BASE-T  
collision window, making the maximum network diameter smaller.  
In a repeater environment, 100BASE-TX only allows a single layer of  
cascaded hubs.  
Switching hubs, such as LantronixÕs LSW8FA, may increase the  
network diameter for 100BASE-TX networks by buffering data packets.  
Each port can be connected to a separate LAN segment, each with a  
maximum diameter of 205 meters, thereby increasing the overall  
100BASE-TX network diameter.  
5
 
Not only does 100BASE-TX have a different data transmission scheme,  
it also has different cabling requirements. As previously noted,  
100BASE-TX requires data-grade (Category 5) UTP cable.  
Some installations have Category 5 cabling but do not have wall outlets  
and wiring closet punch-down blocks that meet Category 5 require-  
ments. 100BASE-TX requires that all wiring and accessories meet  
EIA/TIA 568B specifications for proper operation. When wiring a  
100BASE-TX network, make sure that the entire cable plant meets  
specifications.  
Figure 2-1 LFH4-M 100BASE-TX Network Example  
LFH4-M  
Uplink  
1
LFH4-M  
2
TITION  
R
A
P
4
3
LINK/ACT  
NO.  
T
POR  
3
2
1
4
PWR  
COL  
Uplink  
1
2
TITION  
R
A
P
4
3
LINK/ACT  
NO.  
T
POR  
3
2
1
4
PWR  
COL  
2.3 Installation  
The LFH Mini Fast Ethernet Hubs are easy to install and require no  
special training. You should, however, read the following instructions  
carefully before proceeding to install your hub. Figures 2-2 and 2-3  
show the layout of the front panels.  
6
 
Figure 2-2 LFH4-M Front Panel  
LFH4-M  
PARTITION  
LINK/ACT  
4
3
2
1
4
3
2
1
Uplink  
PORT NO.  
Figure 2-3 LFH8-M Front Panel  
LFH4-M  
PARTITION  
LINK/ACT  
4
3
2
1
4
3
2
1
Uplink  
PORT NO.  
The LFH Mini Fast Ethernet Hubs were designed for easy Òplug and  
playÓ installation. Before you connect the LFH to other devices, there  
are several issues you should keep in mind:  
When connecting the LFH to a workstation using unshielded  
twisted pair cable, you must make sure that the cable length is not  
greater than 100 meters  
When you connect two LFH hubs, you must make sure that the link  
between them is not longer than 5 meters  
Network cable segments can be connected to, or disconnected from  
the hub while the power is on. Plugging in or removing network  
cables while your hub is operating will not interrupt the operation  
of the hub  
When placing your LFH hub, you need to avoid dusty locations and  
electromagnetically noisy areas  
7
 
2.4 Mounting  
Your LFH4-M or LFH8-M hub is delivered with a mounting bracket.  
The LFH hub can be mounted to the wall or to the surface of a counter-  
top by using the bracket and hanging the LFH hub on the wall using  
the keyholes provided on the bottom of the hub.  
If mounting the LFH hub is not your preference, you may choose to  
place the LFH hub on a table or wiring closet shelf. Use the four self-  
adhesive rubber feet, which are provided with the hub for cushioning  
purposes. Place them on the four corners of the bottom surface of the  
hub.  
8
 
2.5 Connecting the LFH Hub  
Use the following procedures to connect 100BASE-TX network devices  
to the hub:  
LFH4-M  
LFH8-M  
Ports 1-4  
Ports 1-8  
Uplink Port  
PC, Workstation  
Server  
S
S
C
C
S
Hub, Switch port  
Hub, Switch uplink port  
C
S
C
S = Straight Cable C = Crossover cable  
NOTE: If the Uplink Port is being utilized on the LFH hub, the adja-  
cent Port may not be used. Conversely, if that Port is being utilized, the  
Uplink Port may not be connected.  
The following table describes the two cable types:  
Straight cable  
TD+  
Crossover cable  
Pin 1  
Pin 2  
Pin 3  
Pin 6  
RD+  
RD-  
TD+  
TD-  
TD-  
RD+  
RD-  
Make sure that the length of the straight-through cable between the  
LFH hub and the other device does not exceed 100 meters, including all  
patch cables and cross-connect wires.  
Make sure that the length of the straight-through cable between two  
hubs does not exceed 5 meters.  
9
 
Chapter 3 LED Indicators  
Figure 3-1 and Figure 3-2 show the LED indicators which indicate the  
link status of each of the ports, whether the LFH hub is receiving  
power, and the presence of network activity and collisions on the  
network.  
Figure 3-1 LFH4-M Front Panel LED Indicators  
LFH4-M  
Partition  
Link/Activity  
PARTITION  
LINK/ACT  
4
3
2
1
PORT NO.  
Figure 3-2 LFH8-M Front Panel LED Indicators  
LFH4-M  
Partition  
Link/Activity  
PARTITION  
LINK/ACT  
PORT NO.  
4
3
2
1
10  
 
3.1 Power LED  
The green LED on the front panel labeled PWR is used to indicate that  
the LFH hub is receiving power and is turned on. If the LED is off,  
check the following to isolate the problem:  
Make sure the power cord is properly connected to the power outlet  
and is properly inserted into the power connection on the LFH hub  
Determine whether or not the outlet is functional by plugging  
another device into the receptacle  
3.2 Collision LED  
The yellow collision LED is located on the front panel and is labeled  
COL. This indicates that two (or more) stations on the network  
attempted to transmit at the same time. When a collision occurs, all of  
the stations involved will recognize the collision, wait a random  
amount of time, and re-transmit. Collisions are normal in Ethernet  
networks, though excessive collisions may indicate that your network  
is overly congested. Other network problems can cause excessive colli-  
sions, including:  
Workstation cables exceeding the maximum length of 100 meters  
A total network diameter exceeding the maximum 205 meters  
Faulty Fast Ethernet adapters or other equipment on the network  
11  
 
3.3 Link/Activity LEDs  
The Link/Activity LEDs on the front panel are associated with indi-  
vidual ports, indicating whether a device is detected on the other end  
and whether or not the port has been automatically partitioned off.  
The LFH hub monitors each port on the hub to determine whether or  
not there is a device on the other end. If the cable is connected to a port  
and a link is detected, the LED will light; otherwise the LED will not  
light and the transmit and receive functions of the port will be disabled.  
3.4 Partition LED  
The yellow Partition LED is located on the front panel and labeled as  
PARTITION. When there are too many collisions received from a  
specific station(s), the hub will automatically partition it to prevent the  
data transmission from other ports to those specific ports. When this  
port is partitioned, the LED will be turned on.  
3.5 System Status LEDs  
LED summary table  
PWR  
Green  
Yellow  
Yellow  
ON=Unit is receiving power  
ON=Port is partitioned  
PARTITION  
COL  
ON=Collision occurred  
OFF=No collisions  
LINK/ACT  
Green  
ON=Good link; Flashing=Activity  
12  
 
Limited Warranty  
The LFH4-M and LFH8-M come with 5-year limited warranties. To  
obtain LantronixÕs full warranty statement or if you experience prob-  
lems with your unit, check our website (www.lantronix.com) or call  
Lantronix for assistance.  
Copyright © 1998, Lantronix. All rights reserved. No part of the  
contents of this guide may be transmitted or reproduced in any  
form or by any means without the written permission of Lantronix.  
Technical Support  
If problems occur during product operation, please check the hub  
configuration settings, cables, connectors, network terminators and other  
network components for compatibility.  
Write a description of the problem, including what problems occurred and  
when they occurred. Also, please have the following information ready  
if calling for support services:  
Model number & serial number  
Purchase date  
Network configuration  
Application environment  
Hardware, software (NOS) and the DOS version  
Contact Lantronix technical support at 800-422-7044 within the United  
States or 949-453-3990 outside of the United States. LantronixÕs tech-  
nical support can also be reached via email at [email protected],  
and via www.lantronix.com or via fax at 949-450-7226.  
13  
 
WARNING!  
This device complies with part 15 of the FCC rules. Operation is subject  
to the following conditions: (1) this device may not cause harmful  
interference, and (2) this device must accept any interference received,  
including that which may cause undesired operation. Operation of this  
equipment in a residential area is likely to cause interference in which  
case the user, at his or her own expense, will be required to take what-  
ever measures may be required to correct the interference.  
NOTE: The RJ45 ports are not for telephone use.  
CAUTION:  
Not for installation in air ducts, plenums or other environmental  
air handling spaces. Changes or modifications to this device not  
explicitly approved by Lantronix will void the userÕs authority  
to operate this device.  
14  
 
Declaration of Conformity  
(according to ISO/IEC Guide 22 and EN 45014)  
ManufacturerÕs Name: Lantronix  
ManufacturerÕs Address: 15353 Barranca Parkway  
Irvine, CA 92618 USA  
declares, that the product:  
Product Name: Mini Fast Hubs  
Model Number: LFH4-M, LFH8-M  
conforms to the following standards:  
EMC: EN55022(1988)/CISPR 22(1985)  
EN60555-2(1987)  
Class B  
Class A  
prEN55024-2(1990)/IE801-2(1991)  
prEN55024-3(1991)/IE801-3(1984)  
prEN55024-4(1992)/IE801-4(1988)  
4KV CD, 8KV AD  
3V V/m  
1KV - (power line)  
0.5KV - (signal line)  
ManufacturerÕs Contact: Director of Quality Assurance  
Lantronix  
15353 Barranca Parkway  
Irvine, CA 92618 USA  
Tel: 949-453-3990  
Fax: 949-453-3995  
15  
 
NOTES  
16  
 
15353 Barranca Parkway, Irvine, CA 92618  
949-453-3990 Fax: 949-453-3995 Sales: 800-422-7055 Support: 800-422-7044  
PART NO. 900-142 Rev.A  
 

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