Lantronix LFH8-S User manual

LFH8-S/LFH16-S
Fast Stackable Hubs
Installation Guide

Table of Contents
CHAPTER 1. Introduction
1.1 Product Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Product Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
CHAPTER 2. Using the LFH Hub
2.1 Packing Checklist. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Planning 100BASE-TX Networks . . . . . . . . . . . . . . . . . . . . . 5
2.3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5 Stacking LFH8-S/LFH16-S Hubs . . . . . . . . . . . . . . . . . . . . . 9
2.6 Connecting the LFH Hub . . . . . . . . . . . . . . . . . . . . . . . . . . 11
CHAPTER 3. LED Indicators
3.1 Power LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2 Partition LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Link/Receive LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Utilization % LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5 System Status LEDs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Limited Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . 16
1

CHAPTER 1 Introduction
1.1 Product Introduction
Congratulations on your purchase of the LFH stackable 8-port or 16-
port Fast Ethernet Hub! The LFH8-S and LFH16-S are designed to give
you the ultimate in flexibility, ease-of-use, and reliability.
The LFH8-S and LFH16-S Stackable Fast Ethernet Hubs are 100BASE-
TX multiport Class II repeaters designed 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 feature
Link/Receive, Partition, and Utilization % LEDs for convenient moni-
toring of the status of the hub and of each port. The rear panel of each
LFH hub features two stacking ports, allowing up to six LFH stackable
hubs to be combined as a single repeater. For additional expansion, the
LFH8-S/ LFH16-S provides an uplink port that makes it easy to cascade
the hub to another Fast Ethernet hub or hub stack.
The LFH8-S/LFH16-S hubs can be placed on a table top or rack-
mounted, and provide the ideal solution for small to large 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 LFH8-S and LFH16-S 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 LFH8-S provides eight 100BASE-TX ports and the LFH16-S
provides 16 100BASE-TX ports for Fast Ethernet connectivity
▼The LFH8-S/LFH16-S 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 LFH8-S/LFH16-S to
be connected to another 100BASE-TX hub using a straight-through
cable
▼The LFH8-S and LFH16-S stackable architectures enable up to 6
hubs to be stacked together for a total of up to 96 ports
▼Performs preamble regeneration, signal retiming and restoration,
extension of fragmented packets, automatic partitioning, and jabber
truncation
▼Global Power and individual port Link/Receive, Partition, and
Utilization% LEDs indicate system status
▼The internal power supply automatically adjusts to the voltage
range of the AC power being supplied (100VAC/60Hz to
240VAC/50Hz), with no change in settings or fuse required
▼The LFH8-S and LFH16-S come with metal brackets that can be
easily attached to the hub for mounting in a standard 19 inch equip-
ment rack
▼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 100Mbps ports, one crossover ÒUplinkÓ
port
Two 25-pin stacking connectors
Stackable Maximum 6-hub stack, stacking cable included
LED indicators Power, Partition, Link/Receive and Utilization indi-
cators
Dimensions 356mm x 230mm x 44mm (L x W x H)
Environment Temperature: Operating: 0¡C to 40¡C
Storage: -20¡C to 70¡C
Humidity Operating: 10% to 90% RH
Power 100 VAC/60Hz to 240 VAC/50Hz
Certifications FCC Class A, CE, UL, CUL, TUV
Warranty 5-year limited
4

5
Chapter 2 Installing the LFH Hub
2.1 Packing Checklist
Your LFH package should contain the following:
✓An LFH8-S or LFH16-S Fast Stackable Hub
✓One AC Power Cable
✓One 25-pin cable for stacking LFH hubs
✓Mounting brackets and screws
✓Four self-adhesive standoffs
✓Rackmount brackets and screws
✓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.

6
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.
Not only does 100BASE-TX have a different data transmission scheme,
it also has different cabling requirements. As noted above, 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.

2.3 Installation
The LFH Stackable Fast Ethernet Hubs are easy to install and require
no special training. You should, however, read the following instruc-
tions carefully before proceeding to install your hub. Figures 2-1 and
2-2 show the layout of the front panels.
Figure 2-1 LFH8-S Front Panel
Figure 2-2 LFH16-S Front Panel
7
12345678
PWR
UTILIZATION %
PARTITION
LINK/RECEIVE
PORT NO.
LFH8-S
10 60+
1234 5678 Uplink
910111213141516
1234 5678
12345678
PWR
LINK/RECEIVE
PORT NO.
LFH16-S
10 60+
9101112 13141516
Uplink
PORT NO.
PARTITION
LINK/RECEIVE
UTILIZATION %
PARTITION

The LFH Stackable 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 Fast Ethernet hubs or hub stacks
together, you must make sure that the link between them is no longer
than 5 meters
▼Network cable segments can be connected to or disconnected from
the LFH 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
2.4 Mounting
Your LFH8-S or LFH16-S hub is delivered with two brackets for
mounting the hub in an EIA standard 19 inch rack. Secure the
mounting brackets onto the sides of the hub, fastening them with
screws as shown in Figure 2-3.
Figure 2-3 Mounting Bracket Installation
8
8 7 65 43 21
UTILIZATION %
PARTITION
LINK/RECEIVE UPLINK
10 60+

If your site uses only a few hubs and is not equipped with a mounting
rack, you may choose to place the LFH hub on a table or wiring closet
shelf. In this case, use the four self-adhesive rubber feet, which are
provided with the hub for cushioning purposes. Stick them at the four
corners of the bottom surface of the hub to cushion it against vibration.
2.5 Stacking LFH8-S/LFH16-S Hubs
You can stack up to six LFH8-S/LFH16-S hubs together using the
special connectors on the back panel. A single stack can contain a
mixture of 8-port and 16-port hubs. The maximum allowable any of
LFH8-S and LFH16-S hubs in a stack are 6 hubs.
When the LFH hubs are stacked together they are counted as a single
Fast Ethernet repeater, and the entire stack can be chained as a unit to
another Class II hub or hub stack.
To stack two LFH8-S/LFH16-S hubs together (see Figure 2-4):
1. Position the LFH hubs with one on top of the other.
2. Connect one end of the stacking cable to either one of the connectors
on the rear of the LFH hub. Make sure the cable snaps firmly onto
the connector.
3. Connect the other end of the stacking cable to either one of the
connectors on the other LFH hub.
Figure 2-4 Stacking Two Hubs
9
IN
100-240 VAC 1A 50-60 Hz
AC IN
OUT
IN
100-240 VAC 1A 50-60 Hz
AC IN
OUT

10
Similarly, to connect six LFH hubs together in a stack (see Figure 2-5):
1. Position the LFH hubs with one on top of another.
2. Connect a stacking cable from one of the connectors on the middle
LFH hub to one of the connectors on the top LFH hub.
3. Connect a stacking cable from the other connector on the middle
LFH hub to one of the connectors on the bottom LFH hub.
Figure 2-5 Stacking Six LFH8-S/LFH16-S Hubs
100-240 VAC 1A 50-60 Hz
AC IN
OUT
100-240 VAC 1A 50-60 Hz
AC IN
IN
OUT
100-240 VAC 1A 50-60 Hz
AC IN
IN
OUT
100-240 VAC 1A 50-60 Hz
AC IN
IN
OUT
100-240 VAC 1A 50-60 Hz
AC IN
IN
OUT
100-240 VAC 1A 50-60 Hz
AC IN
IN
OUT
IN

11
2.6 Connecting the LFH Hub
Use the following procedures to connect 100BASE-TX network devices
to the hub:
NOTE: If the Uplink Port is being utilized on the LFH hub, Port Ò8Ó
may not be used. Conversely, if Port Ò8Ó is being utilized, the Uplink
Port may not be connected.
The following table describes the two cable types:
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.
Straight cable Crossover cable
Pin 1 TD+ RD+
Pin 2 TD- RD-
Pin 3 RD+ TD+
Pin 6 RD- TD-
LFH8-S Ports 1-8 Uplink Port
LFH16-S Ports 1-16
PC, Workstation S C
Server S C
Hub, Switch port C S
Hub, Switch uplink port S C
S = Straight Cable C = Crossover cable

Chapter 3 LED Indicators
Figure 3-1 shows 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 utilization % and partition on the network.
Figure 3-1 LFH16-S Front Panel LED Indicators
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 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 data trans-
mission to those specific ports. When this port is partitioned, the LED
will be turned on.
12
Partition
Link/Receive
Utilization %
Partition
Link/Receive
910111213141516
12345678
PWR
LINK/RECEIVE
PORT NO.
LFH16-S
10 60+
PORT NO.
PARTITION
LINK/RECEIVE
UTILIZATION %
PARTITION

3.3 Link/Receive LEDs
The Link/Receive LEDs on the front panel are associated with indi-
vidual ports, indicating whether a device is detected on the other end.
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 Utilization % LEDs
The Utilization % LEDs is defined to indicate the current traffic utiliza-
tion of the network. This hub supports 6 LEDs to indicate different
traffic utilization levels.
The table below shows the different status indications of the Utilization
% LEDs:
10~20% Green
30~40% Yellow
50~>60% Yellow
3.5 System Status LEDs
13
LED summary table
PWR Green ON=Unit is receiving power
PARTITION Yellow ON=Port is partitioned
UTILIZATION Green/Yellow Green=10-20% Utilization
Yellow= >30% Utilization
LINK/RECEIVE Green ON=Link is detected

Limited Warranty
The LFH8-S and LFH16-S 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 [e-mail],
and via www.lantronix.com or via fax at 949-450-7226.
14

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.
15

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: Fast Stackable Hubs
Model Number: LFH8-S, LFH16-S
conforms to the following standards:
EMC: EN55022(1988)/CISPR 22(1985) Class B
EN60555-2(1987) Class A
prEN55024-2(1990)/IE801-2(1991) 4KV CD, 8KV AD
prEN55024-3(1991)/IE801-3(1984) 3V V/m
prEN55024-4(1992)/IE801-4(1988) 1KV - (power line)
0.5KV - (signal line)
ManufacturerÕs Contact: Director of Quality Assurance
Lantronix
15353 Barranca Parkway
Irvine, CA 92618 USA
Tel: [phone]
Fax: [phone]
16

15353 Barranca Parkway, Irvine, CA 92618
949-453-3990 ▼Fax: [phone] ▼Sales: 800-422-7055 ▼Support: 800-422-7044
PART NO. 900-143 Rev.A