Lantronix LMR8TT User manual
LMR8TT
Mini 10BASE-T
Hub/Repeater
1
LMR8TT
Ethernet Mini
Hub/Repeater
Installation Guide
The Lantronix LMR8TT is a 10BASE-T Mini hub
that provides wiring connections for up to eight
unshielded twisted pair (UTP) ports. An uplink
port is provided for cascading two hubs.
The LMR8TT constantly monitors each port for
signal quality and will automatically disconnect a
device producing noise or excessive collisions.
The device will automatically be reconnected
when the error condition has cleared.
Data packets that exceed the maximum legal
length for IEEE 802.3 Ethernet packets are
automatically truncated. This prevents a device
from blocking the network by transmitting a
continuous data stream or extra long packet.
The LMR8TT retimes and restores full amplitude
wave forms for each retransmitted packet. A full
length preamble is also generated ensuring
packet integrity across the network.
Compact, light and robust, the LMR8TT
provides the ideal solution for small and medium
10BASE-T LAN environments.
2
Features
▼The LMR8TT is a cost-effective
unmanaged repeater that allows the
interconnection of 10BASE-T segments.
▼The LMR8TT provides an additional UTP
uplink port to enable LMR8TT hubs to be
cascaded together using a standard
'straight' cable.
▼The LMR8TT accommodates cascaded
bus or daisy-chain topologies. Up to 98
ports can be easily daisy-chained per
Ethernet segment
▼The LMR8TT includes preamble
regeneration, signal retiming and
restoration, extension of fragmented
packets and jabber function for automatic
partitioning.
▼Power, collision, activity LEDs and
individual port link LEDs aid network
diagnosis and management
▼The LMR8TT complies with IEEE 802.3
10BASE-T twisted pair standards.
▼The LMR8TT comes with a 5 year
warranty.
3
Cable Requirements
The LMR8TT is for use with standard EIA/TIA
category 3, 4,or 5 10BASE-T cable with an RJ45
connector.
Power Requirements
The LMR8TT comes with a 5VAC external
power adapter with a frequency range of 47Hz
to 63Hz.
Installation
Connecting a 10BASE-T Device
1. Verify that the straight-through cable
distance between the LMR8TT and the
device is not greater than 100 meters,
including all patch cables and cross
connect wires.
2. Connect one end of the straight-through
cable to the RJ45 connector on the
LMR8TT and the other end of the cable to
the station.
4
Cascading the LMR8TT
1. A straight-through cable may be used to
interconnect two LMR8TTs as long as the
cable distance between the two LMR8TT
repeaters is not be greater than 100
meters.
2. The LMR8TT may be interconnected as
long as the path between any two network
stations does not exceed four repeaters
and five cable segments. The diagram
below demonstrates two cascaded
LMR8TTs.
7654321
X88765432
1
X
UTP Port Cascade Port
Fig. 1.1 LMR8TTs in cascade configuration.
5
Modular Jack Pinout
Pin Signal Pin Signal
1 TD+ 5 No Connection
2 TD- 6 RD-
3 RD+ 7 No Connection
4 No Connection 8 No Connection
LED Explanation
The LMR8TT has 10 LEDs that are visible from
the front of the unit. The following chart
explains their meanings.
LED Color LED Name Meaning When Lit
Green Power Lit solidly when
LMR8TT is receiving
power.
Yellow Collision Lit when a collision
occurs
Green Activity/Link Lit when normal data
packets are received
or when link-integrity
pulse is detected
Agency Approvals
FCC Class A, TÜV, UL, CSA, CE
Warranty Information
The LMR8TT comes with a limited 5-year
warranty. If you experience problems with your
unit, check our website (www.lantronix.com) or
call Lantronix for assistance.
Copyright 1997, 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.
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 whatever measures may be required to
correct the interference.
Note: The RJ45 port is not for telephone use.
CAUTION:
Not for installation in air ducts or plenums or
other environmental air handling spaces.
Changes or modifications to this device not
explicitly approved by Lantronix will void the
user’s authority to operate this device.
6
Declaration of Conformity
(according to ISO/IEC Guide 22 and EN 45014)
Manufacturer’s Name: Lantronix
Manufacturer’s Address: 15353 Barranca Parkway
Irvine, CA 92618 USA
declares, that the product:
Product Name: Ethernet Repeater
Model Number(s): LMR8TT
conforms to the following standards:
EMC Directive 89/336/ECC as attested by conformity with the follow-
ing harmonized standards:
EN 55022: Class A, 1986: Limits and Methods of Measurement of
Radio Interference characteristics of Information Technology
Equipment and
EN 50082/1: 1992: Generic Immunity Standard - Part 1: Domestic
Commercial and Light Industry.
Manufacturer’s Contact: Director of Quality Assurance
Lantronix
15353 Barranca Parkway
Irvine, CA 92618 USA
Tel: 949-453-3990
Fax: 949-453-3995
15353 Barranca
Parkway, Irvine CA 92618
949-453-3990 ▼Fax: 949-453-3995
Part No. 900-124
7
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