Listen Technologies LT-84 User manual

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Installation and Operation
LT-84 ListenIR Transmitter/Radiator Combo
LA-141 ListenIR Expansion Radiator
User Manual

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Table of Contents
Safety Cautions! ....................................................................................................................................................................................2
Recycling Instructions........................................................................................................................................................................2
Compliance Information...................................................................................................................................................................3
Compliance Notice, FCC and Industry Canada Statements ..............................................................................................3
System Overview..................................................................................................................................................................................4
LT-84 ListenIR Transmitter/Radiator Combo...........................................................................................................................5
Package Contents.............................................................................................................................................................................5
LT-84 Rear View Quick Reference..................................................................................................................................................5
LA-141 ListenIR Expansion Radiator ............................................................................................................................................6
Package Contents.............................................................................................................................................................................6
LA-141 Rear View Quick Reference...............................................................................................................................................6
LT-84 and LA-141 Coverage...............................................................................................................................................................7
Designing a System..............................................................................................................................................................................9
Flexible Mounting Hardware Instructions............................................................................................................................. 10
Mounting Hardware Kit ...............................................................................................................................................................10
Mounting Provision Thread ¼” x 20 (6mm x 1.0 thread) .................................................................................................... 10
Wall Surface Mounting Example................................................................................................................................................11
Ceiling Surface Mounting Example...........................................................................................................................................11
Mounting Two Units with Linking Mount Example...............................................................................................................11
Interconnection and Control........................................................................................................................................................12
Connection of the External Power Adaptor ...........................................................................................................................12
Connection of External Audio Sources.................................................................................................................................... 13
I/R Frequency Selection/Control...............................................................................................................................................14
ListenIR Expansion Link RJ-45 Connections ........................................................................................................................... 15
Indicator Lights ..............................................................................................................................................................................16
Troubleshooting ............................................................................................................................................................................17
......................................................................................................................................................................18
 ...................................................................................................................................................................19
Warranty Information.....................................................................................................................................................................20
Technical Support Contact............................................................................................................................................................ 21

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Safety Cautions!
CAT-5e Cable Safety:
Do NOT Plug the LT-84 (ListenIR Transmitter/Radiator Combo) CAT-5e cable into anything other than an
LA-141 (ListenIR Expansion Radiator). The LT-84 CAT-5e Expansion Output RJ-45 connection is proprietary
and is not compatible with Ethernet or any other system. Failure to comply with this caution can damage the
LT-84, LA-141 or other equipment and will void the warranty.
Hearing Safety:
The LT-84 is designed to be used with Listen Technologies receivers. These receivers are designed to amplify audio
to a high volume level which could potentially cause hearing damage if used improperly. To protect your hearing,
make sure the volume is turned down before putting on the ear speaker or headphones, then adjust the volume
up to the minimum setting require to hear clearly. Do not allow children or other unauthorized individuals to have
access to this product without supervision.
Medical Device Safety:
Before using Listen Technologies receivers with an implantable or other medical device, consult your implantable
or other medical device physician or manufacturer. Always make sure you are using this product in accordance
with the safety guidelines established by your physician or the implantable device manufacturer.
Recycling Instructions
Recycling:
Help Listen Technologies protect the environment by taking the time to dispose of your equipment properly.
Product Recycling Instructions:
Please do NOT dispose of your Listen Technologies equipment in the household trash. Please take
the equipment to an electronics recycling center; OR, return the product to the factory for proper
disposal.
Battery Recycling Instructions:
Please do NOT dispose of batteries in the household trash. Please take the batteries to a
retail or community collection point for recycling.



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Compliance Information
No FCC license or radio approval is required to operate this equipment.
Compliance Notice,
FCC and Industry Canada Statements
Compliance Notice
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) These devices may not cause harmful interference, and (2) these devices must accept any interference
received, including interference that may cause undesirable operation.
FCC Statement
This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to
part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference
in a residential installation. This equipment generates, uses and can radiate radio frequency energy and if not
installed and used in accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning the equipment

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
  
is connected.
• Consult the dealer or an experienced radio/TV technician for help.

manufacturer could void the user’s authority to operate this equipment.
Industry Canada Statement
This equipment complies with ICES-003 class B.
CAN ICES-3 (B)/NMB-3(B)

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System Overview
The LT-84 is an all-in-one two channel infrared (IR) transmitter and radiator (Transmitter/Radiator Combo) packed
into a single mountable enclosure. The LT-84 IR radiator is located behind the IR transparent front panel and
provides line-of-sight coverage of 30,000 ft2(2787 m2) with LR-4200-IR/LR-5200-IR receivers or 7,500 ft2(697 m2)
with LR-42/LR-44 receivers. .
The LT-84 is perfect for high-quality audio applications like assistive listening, audio description or language

inputs accept microphone, consumer and line level inputs which are all mixed to the modulated IR transmission.
IR receivers then detect the modulated IR transmission and convert the IR signals back into an audio signal and
presents it to headphones.
For better line of sight coverage or for coverage in larger areas the LT-84 can be combined with up to four (4)
LA-141 Listen IR Expansion Radiators. The LA-141s are connected in a daisy chain fashion to the LT-84 via a 24
AWG unschielded CAT-5e cable. A maximum of two (2) LA-141s can be connected to each expansion link output
on the LT-84 with a maximum cable length of 100 ft. (30 m).

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LT-84 ListenIR Transmitter/Radiator Combo
Package Contents
LT-84 ListenIR Transmitter/Radiator Combo
LA-210 12 VDC Universal Power Supply
Power Cord
LA-344 Mounting Hardware
(2) Phoenix Type Connectors
Quick Start Guide
LA-303 Small Room Signage Kit
LT-84 Rear View Quick Reference
Safety/Security
Cable Slot
Mic
Input
Level Control
Knob
Frequency
Selector
Mic
Input
Level Control
Knob
Frequency
Selector
Expansion Link
Output RJ-45
Amber LED
(Status Indicator)
Power Input
Power Switch
Indicator Lights
On/O
RCA Input
(Stereo)
Line Input
Level
Indicators
Transmission
On/O
RCA Input
(Stereo)
Line Input
Level
Indicators
Transmission
On/O
Green LED
(Power Indicator)
LT-84 Rear View
This facility is equipped with a hearing assistance system.
Please ask for a receiver.
Este establecimiento está equipado con un sistema
de asistencia auditiva. Por favor solicite un receptor.
Cet éstablissement est équipé d’un système d’aide
à l’audition. S’il vous plaît demandez un récepteur.
Hearing Assistance Available
Asistencia auditiva a su disposición
Aide à l’audition
LT-84 Stationary IR Transmitter/Radiator Combo
LA-303 Small Room Signage Kit
Quick Start Guide
(2) Phoenix Type
Connectors
LA-344 Mounting Hardware
Power Cord
LA-210 12 VDC Universal Power Supply
Mounting Plate
Cover
Pan & Tilt
1/4” x 20
Mount Adaptor
Ceiling Tile
Mounting Plate
Flush Mounting Plate
2” Extension Bars
All Thread Piece
Pan and Tilt
Lock Screw
Hex Key

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LA-141 ListenIR Expansion Radiator
Package Contents
LA-141 ListenIR Expansion Radiator
(1) 25 ft. (7.6 m) CAT-5e Cable
LA-344 Mounting Hardware
Quick Start Guide
Safety/Security
Cable Slot
Indicator Lights
On/O Switch
Expansion Link
In/Out RJ-45
Amber LED
(Status Indicator)
Green LED
(Power Indicator)
LA-141 Rear View
LA-141 Rear View Quick Reference
LA-141 Listen IR Transmitter/Radiator Combo
Quick Start Guide
(1) 25 ft. (7.6 m) CAT-5e Cable
LA-344 Mounting Hardware
Mounting Plate
Cover
Pan & Tilt
1/4” x 20
Mount Adaptor
Ceiling Tile
Mounting Plate
Flush Mounting Plate
2” Extension Bars
All Thread Piece
Pan and Tilt
Lock Screw
Hex Key
Channel 1
Delay
Compensation
Channel 2
Delay
Compensation

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LT-84 and LA-141 Coverage
The units emit a beam of infrared light from the front panel. Infrared light is not visible to the human eye. Below
is a scaled diagram of the typical line-of-sight IR pattern or “footprint” emitted from the units. When using a unit in
single channel transmit mode the coverage area is 30,000 ft2(2787 m2) and in 2 channel transmit mode the coverage
area is 15,000 ft2(1394 m2). Use the diagrams below when evaluating a given space to determine the number of units
required and placement of those units for best line-of-sight coverage with an LLR-4200-IR or LR-5200-IR receiver.
Figure 1: LT-84 or LA-141 Single Unit Coverage Pattern “footprint” 1 & 2 Channel Transmission
Figure 2: LT-84 and LA-141 Single Channel Coverage Pattern “footprint” from same emission point
(40% increase)

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Figure 3: LT-84 and LA-141 Single Channel Coverage Pattern “footprint” Overlapping 50 ft. (15.24 m) apart
Figure 4: 
Figure 5:

Examples below are provided for design concept only and do not represent the actual LT-84 coverage pattern “footprint”.
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Designing a System
Use the following steps when designing an IR system:
1. Determine the number of audio channels that will be used (1 or 2).
2. Determine the room size and shape.
3. Use the room size and shape information along with the appropriate 1 or 2 channel coverage
pattern footprint to overlay the footprint on the room dimensions and determine the number of
units required and the placement of those units to cover the desired listening audience.
Best performance is achieved:
• When radiators face and have direct line-of-sight to audience.
• When a system provides over-lapping coverage (like a sprinkling system).
• When special coverage is provided for shaded areas like under a balcony.
• When mounted above and angled down into the listening audience
9 – 16 ft. (2.8 - 4.9 m) high and at an angle between 10 and 30 degrees.
Over-Lapping Coverage
Direct Line-Of-Sight Coverage
Shaded Balcony Area