Listen Technologies LT-800 User manual

TM
User’s Manual
for all Listen Products
LISTEN
TECHNOLOGIES
CORPORATION
© Copyright 1999 Listen Technologies Corporation
TM
LISTEN TECHNOLOGIES CORPORATION
P.O. Box 683010
Park City, Utah 84068-3010 U.S.A.
Shipping: 1762A Prospector Avenue Park City, UT 84060
Telephone: [phone]
Toll Free: 1.800.330.0891
Fax: [phone]
Internet: www.listentech.com
E-Mail: [email protected]
Printed in U.S.A. 10/99
(c) Copyright 1999 Reprint with permission only
productmanual 11x17.qrk 10/11/99 2:42 PM Page 1

2LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
216MHz Frequency Compatibility Table (Continued)
INTRODUCTION
Assistive Listening Systems help enhance the ability to
hear in many applications. These systems deliver audio
directly to a person’s ear through an earphone. This
earphone can be used in conjunction with a hearing aid
or placed directly on the ear. The earphone is
connected to a receiver, which picks up a broadcast
transmission of an audio source. Volume can be
adjusted by the user. Audio originates from a person
speaking into a microphone or sound system.
Assistive Listening Devices are commonly available in
facilities such as places of worship, stadiums, arenas,
meeting rooms, schools, etc. In various public
facilities in the U.S.A., assistive listening device
accessibility is mandated by the Americans with
Disabilities Act, and must be provided by the facility for
the hard of hearing.
Listen’s FM Assistive Listening Systems, in particular,
are extremely versatile, durable and easy to set up and
use. 100% compatible with all major manufacturers of
FM assistive listening products, Listen products offer
access to 57 channels at 72MHz or at 216MHz. This
means that if you have a Listen receiver and walk into a
facility, simply press “SEEK” to find the transmitting
channel. 57 channels also more likely guarantee that a
facility manager can find a clear transmission channel
to broadcast on or can easily change channels if
interference becomes a problem. Also, Listen’s
receivers and portable transmitter feature high
performance NiMH batteries which allow for hassle-
free, long battery life. Another unique feature is
Listen’s LCD Display, which communicates battery
level, channel and RF signal strength.
Listen is dedicated to whatever-it-takes customer
support. We even offer a Limited Lifetime Warranty
that assures maximum performance and no hassle.
Contact Listen; we’ll be happy to assist you.
Introduction
productmanual 11x17.qrk 10/11/99 2:42 PM Page 2

TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
30 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone] Internet: www.listentech.com
All specifications are subject to change without notice.
216MHz Frequency Compatibility Table Table of Contents
Frequency & Compatibility Tables
72MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28-29
216MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30-31
LR-500 Programmable Display Receiver
and LR-400 Display Receiver
Differences in the LR-400 and LR-500 . . . . . . . . . . . .21
Preparing Listen receivers for use . . . . . . . . . . . . . . .21
Operating the Listen receiver . . . . . . . . . . . . . . . . . . .22
Locking into only one channel . . . . . . . . . . . . . . . . . .23
Receiver LED indicator . . . . . . . . . . . . . . . . . . . . . . .23
Receiver battery status icon . . . . . . . . . . . . . . . . . . .23
LR-400 and LR-500 Look & Listen™
LCD display descriptions . . . . . . . . . . . . . . . .23
Unlocking and locking the access door . . . . . . . . . . .24
Charging batteries using SmartCharge™. . . . . . . . . . .24
Operating the receiver with a wall transformer . . . . .25
LR-400 and LR-500 specifications . . . . . . . . . . . . . . .26
Receiver troubleshooting . . . . . . . . . . . . . . . . . . . . . .27
LR-500 programming . . . . . . . . . . . . . . . . . . . . . . . . .25
MISCELLANEOUS
Technical Service Contacts . . . . . . . . . . . . . . . . . . . . . . . . .4
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Compliance Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Limited Lifetime Warranty . . . . . . . . . . . . . . . . . . . . . . . . . .5
LT-800 Stationary Transmitter
Preparing the LT-800 for use . . . . . . . . . . . . . . . . . . . . . . .6
Lock into or unlock a channel . . . . . . . . . . . . . . . . . . . . . .7
Audio connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Antenna set up options . . . . . . . . . . . . . . . . . . . . . . . . . . .8
LT-800 front illustration: controls & display descriptions . .9
Audio controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Operating the unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Selecting a channel to transmit on . . . . . . . . . . . . . . . . .10
LT-800 specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
LT-800 troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .12
LT-700 Portable Transmitter
Preparing the LT-700 for use . . . . . . . . . . . . . . . . . . . . . .13
Operating the unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Selecting a channel to transmit on . . . . . . . . . . . . . . . . .15
Look & Listen™ LCD display descriptions . . . . . . . . . . . .15
LT-700 programming . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Locking into only one channel . . . . . . . . . . . . . . . . . . . . .16
LED indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Battery status icon . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Locking the access door . . . . . . . . . . . . . . . . . . . . . . . . .17
Charging batteries using SmartCharge™. . . . . . . . . . . . . .17
Operating the unit with a wall transformer . . . . . . . . . . . .18
LT-700 troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .19
LT-700 specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
LR-500
Programmable
Display Receiver
LR-400
Display Receiver
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TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
4LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
Compliance Notices
Listen’s Models LT-800, LT-700, LR-400 and LR-500
These devices comply 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 undesired operation.
Listen’s LT-800 and LT-700 Transmitters (216MHz only)
Listen’s LT-800 and LT-700 transmitters are authorized by rule under the Low
Power Radio Service (47 C.F.R. Part 95) and must not cause harmful interference
to TV reception or United States Navy SPASUR installations. You do not need an
FCC license to operate these transmitters. These transmitters may only be used to
provide: auditory assistance to persons with disabilities, persons who require
language translation, or persons in educational settings; health care services to
the ill; law enforcement tracking services under agreement with a law
enforcement agency; or automated maritime telecommunications system (AMTS)
network control communications. Two-way voice communications and all other
types of uses not mentioned above are expressly prohibited.
Caution: Changes or modifications not expressly approved by the party
responsible for compliance could void the user’s authority to operate Listen’s
equipment.
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 off and on, the user is encouraged to
try to correct the interference by one or more of the following measures:
4 Reorient or relocate the receiving antenna.
4 Increase the separation between the equipment and receiver.
4 Connect the equipment into an outlet on a circuit different from that to
which the receiver is connected.
4 Consult the dealer or an experienced radio/TV technician for help.
This equipment has been certified to comply with the limits for a class B
computing device, pursuant to FCC Rules. In order to maintain compliance
with FCC regulations, shielded cables must be used with this equipment.
Operation with non-approved equipment or unshielded cables is likely to
result in interference to radio and TV reception. The user is cautioned that
changes and modifications made to the equipment without the approval of
manufacturer could void the user’s authority to operate this equipment.
Technical Service Contacts & Compliance Notices
Technical Service Contacts
If technical service is needed, please contact
Listen. Pre-authorization is required before
returning Listen products. If products were
damaged in shipment, please contact the carrier,
then contact Listen for replacement or repair
requirements payable by the carrier.
Toll Free: 1.800.330.0891
Telephone: [phone]
Fax: [phone]
Internet: www.listentech.com
General E-Mail: [email protected]
Shipping Address:
Listen Technologies Corporation
1762A Prospector Avenue
Park City, UT 84068-3010 U.S.A.
Correspondence Mailing Address:
Listen Technologies Corporation
P.O. Box 683010
Park City, UT 84068-3010 U.S.A.
TM
72MHz Frequency Compatibility Table (continued)
FCC ID Numbers:
LT-800-072 (72MHz base transmitter) ID: OMD800-001
LT-800-216 (216MHz base transmitter) ID: OMD800-216
LT-700-072 (72MHz portable transmitter) ID: OMD700-001
LT-700-216 (216MHz base transmitter) ID: OMD700-216
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TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
Listen Technologies Corporation (Listen) warrants its products to
be free from defects in workmanship and material under normal
use and conditions for the useful lifetime of the product from date
of purchase. Accessories are warranted for ninety days from date
of purchase. This warranty is only available to the original end
purchaser of the product and cannot be transferred. Warranty is
only valid if warranty card has been returned within 90 days of
purchase. This warranty is void if damage occurred because of
misuse or if the product has been repaired or modified by anyone
other than a factory authorized service technician. Warranty does
cover normal wear and tear on the product or any other physical
damage unless the damage was the result of a manufacturing
defect. Listen is not liable for consequential damages due to any
failure of equipment to perform as intended. Listen shall bear no
responsibility or obligation with respect to the manner of use of
any equipment sold by it. Listen specifically disclaims and negates
any warranty of merchantability or fitness of use of such
equipment including, without limitation, any warranty that the use
of such equipment for any purpose will comply with applicable
laws and regulations. The terms of the warranty are governed by
the laws of the state of Utah.
Listen will only accept returned products with prepaid shipping and
with a return authorization number. To receive a return
authorization number call 1.800.330.0891 or +1.435.647.0316.
Listen will refund the purchase price of the product to the original
purchaser within the first ninety days after purchase if the product
does not perform better than a similar competitive product subject
to an annual amount to any one original purchaser not to exceed
$1,000 and subject to the conditions of this limited warranty. This
is called our Whatever-It-takes Performance Guarantee. Refunds
will only be given to the original purchaser of product once the
product has been returned to the factory in good working order
with an explanation for the refund. To receive a refund, call Listen
for a return authorization number. Return the product with a letter
on the end user’s letterhead stating the reason for the refund and a
copy of the original invoice. If the product was purchased through
a dealer, refunds must be processed through the original dealer.
In the first ninety days after purchase, any defective product will
be replaced with a new unit. After ninety days, Listen will, at its
own discretion either replace the unit with a new unit or a unit of
similar type and condition. Product that is not covered under
warranty shall be replaced with a unit of similar type and condition
based on a flat fee.
This limited lifetime warranty, prices and the specifications of
products are subject to change without notice.
Listen Limited Lifetime Warranty
Limited Lifetime Warranty, Including Performance Guarantee
28 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone] Internet: www.listentech.com
All specifications are subject to change without notice.
72MHz Frequency Compatibility Table
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TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
The LR-400/LR-500 has no power.
Make sure the unit has either fully charged batteries or a Listen
approved wall transformer connected to the unit. Make sure
the VOLUME knob has been rotated to the ON position. If this
does not work, try a different set of batteries. Make sure the
batteries are installed properly.
There is no audio.
Make sure you have turned the volume control up. Make sure
the earphone jack is plugged all the way in to the top of unit.
Make sure the transmitter is broadcasting an audio source.
Make sure you're tuned to the same channel as the transmitter.
If the RF signal is too weak, the receiver will squelch and thus
mute the audio source; move closer to the antenna or turn up
the RF signal strength on the transmitter if possible.
The audio is distorted.
Make sure you're receiving on the correct channel.
There is interference.
Try different frequencies until you find a clear channel. If this
does not work, try a different frequency band (i.e. if you're
using 72MHz, try 216MHz or vice versa). This is accomplished
by returning the equipment to Listen (at no charge).
I cannot pick up the signal on the receiver.
Check to make sure the receiver and the transmitter are on the
same frequency.
I can pick up the signal on the receiver, but it sounds
like it's not tuned in.
Check to make sure the transmitter and receiver are on exactly
the same channel number/letter.
I'm using another brand of transmitter - how do I tell
which channel to use?
Refer to Listen’s Frequency Compatibility Tables (included on
pages 28-31). Either adjust the transmitter or the receiver to a
common channel.
There is not sufficient range.
Make sure you are located as close to the antenna of the
transmitter as possible. Try to locate the antenna as high as
possible and free from obstacles.
It's confusing for users to have 57 channels when
switching between channels.
Use the programming feature of the LR-500 (only) to limit the
number of channels users have access to.
Users keep changing channels.
You can prevent users from changing channels by pressing the
SEEK button and holding it for 10 seconds. This will lock the
channel. On the LR-400, simply lock the access door to prevent
users from accessing channel buttons.
I cannot change channels when pressing the UP and
DOWN buttons.
The unit is locked. Press the SEEK button for 10 seconds to
unlock.
When I change channels, only certain channels are
accessible.
The unit has been programmed to tune to only certain channels
(LR--500 ONLY!). You can change these tunable channels by re-
programming the unit.
How can I limit access to the batteries?
Use the side door locks.
My batteries are not charging.
Make sure the battery switch is in the NiMH position. Make
sure you have connected an approved Listen charging
transformer. Make sure you use ONLY NiMH batteries provided
by Listen. Never try to charge alkaline or NICAD batteries.
I want to run the unit from a wall transformer.
Simply plug a Listen approved transformer to the
CHARGE/POWER connector. Batteries need not be installed,
however, NiMH will recharge if installed while the unit is being
used.
Receiver Troubleshooting
LR-400 and LR-500 Receiver Troubleshooting
LR-400 &LR-500 RECEIVERS
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LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
TM
LT-800 Stationary Transmitter Controls & Audio Connections
26 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LR-500 Specifications
RF Frequency Range:
72MHz: 72.05 - 75.95MHz
216MHz: 216.025 - 216.975 MHz
Sensitivity:
.6uV typical, 1uV maximum for 12dB SINAD
Max deviation at ± 70kHz
Signal to Noise ratio:
wide band channels, 60dB
narrow band channels, 54dB
Frequency Response:
50Hz to 15KHz, ± 3dB
Distortion:
< 2% THD
Squelch:
40dB with loss of RF signal
Antenna:
Uses headphone cable
Available Channels:
72MHz: 17 wide band, 40 narrow band
216MHz: 19 wide band, 38 narrow band
Physical Dimensions:
3” W x 1”D x 5”H
(7.6cm W x 2.5cm D x 13cm H)
Weight:
< 1 lb. (.45 kg) with batteries
Door:
CHANNEL and SEEK buttons are accessible
through door, lockable
Programmability:
Allows only programmed channels to appear on the display, user
functions can be locked by pressing the Seek button for >3
seconds
Power:
Two AA batteries, high capacity alkaline or NiMH rechargeable;
external power connector 8-9 VDC, tip positive, <300mA
Battery Life:
40 hours with high capacity alkaline,
20 hours with rechargeable NiMH
Headphone Output:
750mV RMS maximum at 25kHz deviation,
32 ohms, 3.5MM mono or stereo
LR-400 Specifications
RF Frequency Range:
72MHz: 72.05 - 75.95MHz
216MHz: 216.025 - 216.975 MHz
Sensitivity:
.6uV typical, 1uV maximum for 12dB SINAD
Max deviation at ± 70kHz
Signal to Noise ratio:
Wide band channels, 60dB
Narrow band channels, 54dB
Frequency Response:
50Hz to 15KHz, ± 3dB
Distortion:
< 2% THD
Squelch:
40dB with loss of RF signal
Antenna:
Uses headphone cable
Available Channels:
72MHz: 17 wide band, 40 narrow band
216MHz: 19 wide band, 38 narrow band
Physical Dimensions:
3” W x 1”D x 5”H
(7.6cm W x 2.5cm D x 13cm H)
Weight:
< 1 lb. (.45 kg) with batteries
Door:
Channel and Seek buttons are located behind door, door can be
locked
Programmability:
User functions can be locked by pressing the SEEK button for
>3 seconds
Power:
Two AA batteries, alkaline or NiMH
rechargeable; external power connector
8-9 VDC, tip positive, <300mA
Battery Charging:
Fully automatic, <12 hours
Battery Life:
40 hours with high capacity alkaline,
20 hours with high capacity NiMH
Headphone Output:
750mV RMS maximum at 25kHz deviation,
32 ohms, 3.5MM mono or stereo
Listen Receivers: LR-500 and LR-400 Specifications
LT-800 Transmitter
LINE OUTPUT – the LINE
OUTPUT connector is a mixed
output of INPUT 1 and INPUT 2
after processing. This is an
unbalanced phono connector.
The output level is –10dBm.
INPUT 2 SWITCH: Select
LINE or SPEAKER on the slide
switch directly next to the
INPUT 2 connector. In the
line position, the input level is
–10dBm, and on speaker, the
input level is +10dBm.
INPUT 1 CONNECTION: Connect a
microphone or balanced line level
input. See Preparation instruction
#7 for details (Page 9).
INPUT 1 SWITCH: Select MIC or
LINE input on the slide switch. For Mic
input, the level is –55dBm and the
input impedance is 50 ohms. In the
line position, the input level is +4dBm
and the input impedance is 600 ohms.
INPUT 2 CONNECTION:
this is a phono connector
used to connect an
unbalanced, high imped-
ance line or speaker input
LT-800 Audio Connections
The LT-800 has two possible audio inputs:
INPUT 1 is used to connect a balanced mic or line level input.
INPUT 2 is used to connect an unbalanced, high impedance line input or speaker input.
Indicates RF output power
(full, 1/2 or 1/4) –
select on rear panel
SELECT
CHANNEL
PROCESS: Adjust the amount of
audio processing – to make all audio
sources sound like they are at the
same level, adjust clockwise
CONTOUR: Adjust voice
intelligibility equalization
for your application
requirements
Channel the unit
is tuned to
INPUT: Adjust audio input
levels of Inputs 1 and 2
Activates a tone to
aid tuning of non-
Listen receivers
Indicates audio
input level of
Inputs 1 and 2
Shows audio level
after processing
Plug in a headset
then adjust volume
Power ON/OFF
LT-800 Front Illustration: Controls & Displays
TO LOCK: press both UP and
DOWN buttons simultaneously
to lock channel; press both
again to unlock
If decimal place
is lit, channel is
locked
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8LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-800 Stationary Transmitter Preparation
TM
TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
Charging the Batteries (continued)
5. Plug a wall transformer into the side of the Listen receiver or
place receiver in a Listen Battery Recharging Tray.
6. Once the batteries are fully charged, the unit will stop charging
the batteries. Full-charge will be indicated when all the battery
symbol segments are illuminated and the LED near the volume
control is glowing steadily.
7. The unit can be operated while batteries are charging.
Operating the Receiver with a Wall Transformer
1. The unit will operate normally when connected to a wall
transformer.
2. Batteries do not need to be installed in the unit operate from a
wall transformer.
LR-500 Receiver Programming
1. The LR-500 can be programmed to operate on a limited number of
channels. (The LR-400 cannot be programmed.) For applications
where users are required to select a channel (such as language
translation or classrooms), and you don’t want them to have to go
through all of the available channels, this feature is ideal. If all
channels where available, the user could have 57 channels to
select from.
2.
3. Use the UP and DOWN keys to
select channels. As channels
are displayed, the L/O symbol on
the LCD display will be displayed
for those channels that are
locked out. When a channel is
locked out, the channel is not
available to the user. To toggle
between locked out and not
locked out, press the SEEK
button.
4. To adjust squelch, the padlock icon
will appear after you program your
channels in PROGRAM mode. You
should still be in PROGRAM mode.
To NOT adjust squelch, don’t press a
button for 4 seconds and the unit will
exit PROGRAM mode. To adjust
squelch, press SEEK to unlock
squelch (the padlock will disappear).
The squelch level will appear as a number of dots showing. No dots
means no squelch. The more dots displayed in this mode, the more
sensitive squelch will be. The factory default setting is four dots.
Press the UP button to rotate through the number of dots.
Listen Receivers: LR-500 and LR-400, Charging (cont.) & Programming
To enter PROGRAM mode, press
the UP and DOWN keys simultane-
ously until the PGM symbol is
displayed on the LCD display.
To toggle
between
locked out
and not
locked
out, press
the SEEK
button.
On each channel, check to see if
“L/O” is displayed; it means
channel is locked out from the user
5. To exit PROGRAM mode, don’t press a key for 4 seconds.
4Connect Antenna: Connect the supplied
antenna according the instructions that come with the
antenna. Only use an antenna supplied by Listen.
Connect external
antenna here, or...
Connect whip or
rubber ducky antenna
through cover here
Preparing the LT-800 for Use
1Remove the product from the shipping
container and plastic cover. Inspect for physical
damage. See "Technical Service Contacts" (Page 4) if
damage has occurred.
2For Rack Mounting: If rack mounting the unit, install
the rack mount shelf according the instructions that come
with the shelf, then install the unit and shelf in the rack.
3Plug in Wall Transformer Plug the connector
on the wall transformer into the power connector on
the back panel. Use strain relief on far left side of rear
panel. Do not plug into power source yet. (Only use a
Listen supplied transformer.)
5Set the RF POWER: Set the RF POWER switch for
FULL, 1/2 or 1/4. (Level is also indicated on the front
panel.) The amount of transmitted RF power that you will
need depends on your application. If you are operating
other transmitters in the same environment and receivers
can be used close to the antenna, it is best to have the
transmitter’s output power at its lowest level to reduce
the possibility of interference.
2.Press to
turn power
ON
3. Select channel
using UP and
DOWN buttons
6Power Up
1.Plug transformer into outlet
4. If desired, lock in
selected channel by
pressing both UP and DOWN
buttons simultaneously
Lock Into or Unlock A Channel
TO LOCK: Press the LT-800’s channel UP and DOWN buttons
simultaneously for three or more seconds until you see a
decimal dot light up next to the channel number.
To UNLOCK: Press the channel UP and DOWN buttons
simultaneously for three or more seconds until you see the
decimal dot next to the channel number disappear.
LR-400 &LR-500 RECEIVERS
Batteries will be fully charged when red LED shines solid red.
(LED and battery symbol will flash slowly while charging.)
For charging using a
transformer: with NiMH
batteries in unit, plug wall
transformer in CHARGING
connection and into wall
outlet (as shown).
In PROGRAM mode on the LR-500,
dots indicate level of squelch
productmanual 11x17.qrk 10/11/99 2:43 PM Page 8

LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
TM
LT-800 Stationary Transmitter Preparation & Audio Control
LT-800 Audio Control
(Refer to LT-800 Controls & Displays Illustration on Page 7.)
The LT-800 incorporates automatic audio level control and
processing. Input levels can be viewed on the two VU meters
on the front panel.
1. ADJUST INPUT: Adjust INPUT knob counter-clockwise
to add gain to INPUT 1. Adjust INPUT knob clockwise to add
gain to INPUT 2. If you have two audio sources connected to
both INPUT 1 and 2, adjust the level of one input using the
VU meter, then adjust the output level of the other audio
source.
2. ADJUST CONTOUR: Adjust the CONTOUR knob
counter-clockwise. If most of your audio source is voice,
adjust clockwise for music. The CONTOUR knob adjusts the
relative equalization of the unit. This equalization boosts or
cuts frequencies above 3kHz.
3. ADJUST PROCESS: Adjust the PROCESS knob
clockwise if you want more processing. This will provide for
even more consistent levels. This knob adjusts processing,
relative to automatic processing already performed in the
unit. The LT-800 provides dynamic audio processing intended
to keep audio levels consistent to the listener. When the
PROCESS knob is rotated fully clockwise, all audio is at the
same relative level. When rotated fully counter clockwise,
more dynamic range is provided for the transmitted audio source.
If you’d like to disable the audio processor or make it more
aggressive, contact Listen Technical Service (Page 4).
24 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
_
_
+
+
Top of Unit and Battery Compartment
Receiver Battery Status Icon
Locking the Receiver’s Access Door
Charging Batteries Using SmartCharge™
1. Listen’s LR-400 and LR-500 receivers are unique because they have
an automatic battery charger built in. That means that when the
Listen receiver is connected to a wall transformer or placed in a
Listen Battery Recharging Tray, NiMH batteries will be charged while
in the receiver. Once batteries are charged, the internal battery
charger will automatically turn off. This prevents overcharging of
batteries, automates the process of charging, and makes it so you
don’t have to remember to unplug the charger.
2. Do not attempt to charge alkaline or any other type of non-NiMH
batteries. Only charge Nickel Metal Hydride (NiMH) batteries within
the LR-500 or LR-400. We recommend that you use NiMH batteries
supplied by Listen.
WARNING: Attempting to charge non-NiMH batteries may
result in physical harm, destruction of property and /or fire.
3. IMPORTANT: To charge NiMH batteries, the BATTERY SELECT
switch must be selected to NiMH. Use a pen or small screwdriver to
the move the switch (located in the battery compartment directly
below the BATTERY SELECT label) to the proper position.
4. Install NiMH rechargeable batteries in the battery compartment
ensuring that proper polarity has been observed.
Listen Receivers: LR-500 and LR-400, Batteries
When the battery is fully charged,
all three segments of the battery
symbol will be displayed, as shown.
As fewer battery segments are displayed, the
lower the battery level, as shown.
When the batteries are almost fully discharged, the
battery segments and the red LED near the volume
control will blink quickly. When this occurs, less than
5% of the battery life is remaining and the batteries
should be immediately replaced or recharged.
To unlock: On both
the right and left
side, unlock by
turning slot
horizontal as shown.
To lock: On both the
right and left side,
lock door by turning
slot vertical as
shown.
For only NiMH batteries: set
BATTERY SELECT switch to
NiMH. For all other batteries, set
BATTERY SELECT at alkaline.
LT-800 Transmitter
9Use the headset jack to listen to
audio source – With the audio source or
sources active and the unit powered ON, plug a
headset into the jack located on the LT-800’s front
panel to listen to the audio source. Adjust headset
volume to a comfortable level.
7Connect Audio Inputs: Connect audio source(s) to
one or both audio input connections: Input 1 offers a
choice of balanced XLR or 1/4” phone connection. Input 2
is an unbalanced phono connector. (See LT-800 Audio
Connections on Page 7 for specific connection instructions.)
Balanced Input 1 connection:
XLR or 1/4” phone
Unbalanced Input 2 connection:
phono connector
Input 2 Switch Input 1 Switch
8Adjust Audio Input Switches – For Input 1
Switch, select MIC or LINE input level; Input 2 Switch,
select LINE or speaker level. (See illustration on Page 7.)
Connect balanced and unbalanced audio sources as shown in
diagram. Make sure that if you are connecting an unbalanced
audio source, that Pin 2 of the XLR and the ring of 1/4” phone
jack are connected to ground as shown.
XLR Wiring 1/4” Phone Wiring
The status of the battery
is indicated by the battery
symbol on the LCD.
This segment will blink when batteries are low.
productmanual 11x17.qrk 10/11/99 2:43 PM Page 9

Operating the LT-800
1Make sure the unit is powered on.
2Select a channel – Select the channel to transmit
on to by pressing the channel UP and DOWN buttons. See
"Selecting a Channel to Transmit On" to the right.
Can’t change the channel? It may be locked. Press both the
UP and DOWN buttons simultaneously for 3 seconds until the
decimal dot next to the channel turns off. Press again to lock in
new channel, if desired.
At 72MHz: The LT-800 at 72MHz operates on 17 wide
band channels and 40 narrow band channels:
Letters = Wide Band Channels
Numbers = Narrow Band Channels
At 216MHz: The LT-800 at 216MHz operates on 19 wide
band channels and 38 narrow band channels:
“2” as left digit = wide band channel
“1” and “3” left digits = narrow band channels
Please refer to the Frequency Compatibility Tables (Pages 28-31) for
specific frequencies and compatibility with other manufacturers.
4 NOTE: Operating on a narrow band channel will have less
fidelity and more noise.
3Test Tone, if necessary:To broadcast a tone, press the
test tone button. This button is used to tune other manufacturer
receivers or to identify a particular channel on a receiver.
Selecting a Channel to Transmit On
Selecting a clear channel to broadcast is important for interference-
free broadcasting.
Wide Band Recommendation – If you don’t plan to have
other transmitters (or a limited number) operating in the same area,
it is recommended that you use wide band channels. These are the
most common channels used. Many people own receivers that will
operate on these channels. In addition, wide band channels offer
the best fidelity and the lowest noise. In this case, select one of the
17 wide band channels A through R on 72MHz systems (19 wide
band channels beginning with “2” on 216MHz systems). The best
way to select a channel is by trial and error. Try a channel, if it has
low interference and reliable performance, stick to that channel.
Compatibility with other manufacturers – If you are
using other manufacturer’s receivers with the LT-800, find out their
frequency, then refer to Listen’s Frequency Compatibility Tables
(Pages 28-31) to find the LT-800 channel number or letter that
corresponds with the receiver’s frequency. As much as possible,
Listen has duplicated the wide band channel letters to cover
frequencies of other major brands. However, we recommend
verifying corresponding channel numbers and letters on the tables
on pages 28-31.
If you are using other manufacturer’s receivers and the sound is
distorted, it is probably because the receiver is not designed to
handle the ±25kHz deviation of the Listen transmitter. This can be
corrected by turning the PROCESSOR control knob all the way counter-
clockwise and turning the INPUT LEVEL knob down. Or, call Listen
Technical Service (Page 4) to adjust the transmitter deviation internally.
Several transmitters operating in the same
environment – For this, you’ll need to choose your transmitting
frequencies carefully. The following guidelines should be used to
choose channels:
a. If possible, use all wide band channels. These channels
offer better fidelity and lower noise.
b. Select channels that have the highest frequency separation as
possible (see Frequency Compatibility Tables, pages 28-31), to avoid
adjacent channels and interference. Channels should be at least
200kHz apart.
c. Through a process of trial and error select a combination of
channels that offer the lowest interference and highest reliability.
10 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-800 Stationary Transmitter, Operation & Selecting a Channel
Press POWER button and verify power
connections. When “ON”, display should be lit.
TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
Locking into Only One Channel Receiver LED Indicator
Listen Receivers: LR-500 and LR-400, Locking & Indicators
To lock the receiver so users
cannot change the channel, press
the SEEK button until the LOCK
symbol is displayed.
When locked, the unit will display
the LOCK symbol.
To unlock the channel, press
and hold down the SEEK button
until the LOCK symbol disappears
on the display.
TM
CH
PGM L/O
Letters and numbers indicate the channel the unit is tuned to.
Battery indicator – flashes slowing when
charging, quickly when almost discharged
When the LISTEN logo is
displayed, the unit is
operating normally
In OPERATING mode, this icon indicates the
channel is locked and cannot be changed by
the user (to lock/unlock, press the SEEK button
until the LOCK symbol on the LCD display is
displayed / not displayed).
Indicates the unit is in
PROGRAM mode (to
enter PROGRAM mode,
press UP and DOWN
until the PGM symbol
on the LCD display is
shown.)
In PROGRAM mode (PGM
symbol is displayed), icon
indicates the channel is
locked out and the user does
not have access to the
channel.
LR-400 and LR-500 Receivers: Look & Listen™Display Descriptions
Small dots indicate the relative RF signal strength. When there is no
signal the unit is squelched and the LISTEN logo in extinguished.
Steady Green LED =
Proper Operation
Slow Flashing = Battery
is Low
Slow Flashing when
Charging = Unit is
Charging
LR-400 &LR-500 RECEIVERS
productmanual 11x17.qrk 10/11/99 2:43 PM Page 10

TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
RF Frequency Range:
72MHz: 72.05 - 75.95MHz
216MHz: 216.025 - 216.975 MHz
Transmitter Stability:
50 PPM
Frequency Response:
50Hz to 15kHz, within ±3 db
Modulation Type:
FM, ±25 kHz wide band,
±7.5kHz narrow band
Output Power:
72MHz: 8000uV at 3 meters
216MHz: 100mW
(Max allowed by FCC)
Signal to Noise ratio:
Wide band channels, 60dB
Narrow band channels, 54dB
Antenna:
72MHz: Telescoping (recommended), Helical
Rubber Ducky or Remote Base
216MHz: Whip, Remote Base, Ground
Plane or Directional Antenna
Available Channels:
72MHz: 17 wide band, 40 narrow band
216MHz:19 wide band, 38 narrow band
(Modulation is automatically switched when
changing between narrow and wide band channels)
RF Power Selection:
Full, 1/2, 1/4
Physical Dimensions:
8” W x 8”D x 1.75”H
(20.3cm W x 20.3cm D x 4.45cm H)
Optional rack mount kit, see Page 17
Weight:
3 lbs. (1.4 kg)
Power:
15 VAC/1 amp
Audio Input 1:
F-XLR / 1/4” Phone, 50/600 ohms, balanced
-55dBm / +4dBm, selectable, bridging
Audio Input 2:
Phono, 10k/50 ohms, unbalanced
-10dBm / +20dBm, selectable, adjustable
Audio Output (Mix):
Phono, 10k ohms, unbalanced, -10dBm
Headphone Output:
250mW, 32 ohms, 3.5MM stereo
Controls:
Mix, Process, Contour, Headphone Level,
Tone, RF Power Output, and ON/OFF
Visual Indicators:
Audio input levels 1, 2 and post processed
modulation level; channel; RF power, test tone
LT-800 Stationary Transmitter Specifications
Specifications subject to change without notice.
LT-800 Stationary Transmitter Specifications
22 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
5Place Batteries in Unit Place two AA batteries in
the compartment, making note of the battery polarity shown in
the battery compartment, and again verifying that the BATTERY
SELECT switch is switched correctly for your batteries (see Step 4).
6Place an earpiece or headset in the mini
jack on the top of the unit. The LR-500 and LR-400 are
designed to work with either mono or stereo connectors.
NOTE: Listen receivers accept mono or stereo jacks.
7Turn the receiver on by rotating the volume knob
counter-clockwise. The red LED should activate and the LCD
display should illuminate. If they do not, check to ensure you
have installed charged batteries and that the batteries have
been installed with the proper polarity.
Operating the Listen Receiver
1Make sure the unit is on by rotating the volume
knob to ON when an earpiece or headset is plugged into the
unit. Listen receivers use the cable of the earphone or headset
as a receiving antenna.
CAUTION: Don’t blow out your ears! Slightly rotate the
volume knob to turn the unit ON while keeping the volume
turned down. Then, adjust volume after listening to earphone.
Operating Listen Receivers (continued)
2Select the channel to transmit on to by
pressing the UP and DOWN buttons.
4At 72MHz: Each LR-400 and LR-500 receiver
at 72MHz operates on 17 wide band channels and
40 narrow band channels.
Letters = Wide Band Channels
Numbers = Narrow Band Channels
4At 216MHz: receivers operate on 19 wide
band channels and 38 narrow bands: Channels
starting with “2” are wide band, and channels
beginning with “1” or “3” are narrow band channels.
Please refer to the Frequency Compatibility Tables section
(Pages 28-31) for specific frequencies and compatibility with
other manufacturers.
4 NOTE: Operating on a narrow band channel will have
less fidelity and more noise.
3Test the Audio: If a transmitter is broadcasting on that
channel, you will be able to hear the audio. If the signal is too
weak, the audio will be muted (squelched).
4Find Audio Transmission: Another way to select a
channel is to press the SEEK button. When you do this, the
Listen receiver looks for the next
channel that is active. Sometimes
the unit will mistake interference for
a real broadcast signal. If you get
interference, simply press the SEEK
button again. The SEEK button will
also likely stop on adjacent narrow band channels, or the wide
band channel associated with the narrow band you are looking
for. Simply continue to press SEEK until you reach the clearest
operating channel.
5Adjust volume control for the best listening level.
Listen Receivers: LR-500 and LR-400
Turn volume
knob counter-
clockwise to
turn unit on
LED should
light up solid
red when unit
is on
LCD display
should illuminate
when unit is on
_
_
+
+
Top of Unit and Battery Compartment
LT-800 Transmitter
productmanual 11x17.qrk 10/11/99 2:43 PM Page 11

12 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
The LT-800 has no power.
Make sure the power transformer is connected to a power
source and is connected to the jack marked "Power Input".
Make sure the POWER button is pressed.
There is no audio or the audio level is too low.
Make sure that you have an audio source properly connected to
INPUT 1 and/or 2. The INPUT 1 or 2 switch must be located in
the correct position for the appropriate input level. For
example: if you are using the output of a mixer on INPUT 2, the
switch should be in the LINE position. If it were in the
SPEAKER position, the level would be too low. Also, check the
INPUT knob to ensure it is properly adjusted. You should be
able to see the VU meter deflect on INPUTS 1 or 2 correspond-
ing with the input level of the audio source. Try connecting a
headset to the front panel jack and adjusting the MONITOR
volume control so that you can listen to the audio source.
The audio is distorted.
Check to make sure you have the input level select switches in
the proper position. You may be providing too much audio level
for the input stage to handle.
There is hum in the audio.
Make sure you have properly grounded the audio source to the
LT-800. Check the connections from the audio source to the
LT-800. If you can, try to use a balanced audio source - this will
reduce the chance of creating hum. Try connecting a ground
from the LT-800 to ground and/or to the ground of the source audio.
There is too much audio processing.
Adjust the process knob counter-clockwise. If there is still too
much processing for your application (or you do not want any
processing), contact Listen technical service.
I don’t want any audio processing.
Call Listen’s Technical Service (Page 4).
There is a tone.
The TEST TONE button has been pressed (its LED light is on).
Push the TEST TONE button to turn off the tone.
I cannot change the broadcast channel.
The unit is locked. To unlock, press the UP and DOWN button
simultaneously for 3+ seconds. You can tell when it's locked
because the decimal is illuminated.
The Audio Input 1 sounds “tinny”.
If you are using an unbalanced audio source, make sure Pin 2
or the XLR and the ring on the 1/4” jack is grounded.
There is interference.
Try different frequencies until you find a clear channel. If this
does not work, try a different frequency band (i.e. if you're
using 72MHz, try 216MHz or vice versa). This is accomplished
by returning the equipment to Listen (no charge) and replacing
it with Listen’s alternate frequency band equipment.
I cannot pick up the signal on the receiver.
Check to make sure the receiver and the transmitter are on the
same frequency.
I can pick up the signal on the receiver, but it
sounds like it's not tuned in.
Check to make sure the transmitter and receiver are on exactly
the same channel number/letter.
I'm using another brand of receiver - how do I tell
which channel to use?
Refer to Listen’s Frequency Compatibility Tables (pages 28-31).
Adjust Listen’s transmitter or receiver to the same frequency as
the other major brand. Since Listen products can access 57
channels, they will most likely transmit or receive on the same
fixed channel or channels of other major ALD brands.
There is not sufficient range.
First make sure that the receivers you are using are operating
properly. Then, make sure that you have an antenna connected
either to the top of the LT-800 transmitter or connected to the
back of the unit (but not both!). Locate the antenna at a
location as high as possible and free of obstacles. Make sure
the antenna is of the correct type and is connected properly to
the unit. Try using different frequencies that don't have
interference. If you're using 216MHz, you might want to try a
directional antenna.
End users are adjusting the unit.
First, lock the channel by pressing the UP and DOWN buttons
together for 3+ seconds. Consider removing the INPUT,
PROCESS AND CONTOUR knobs. You can order from Listen a
rack mount shelf and security cover that will limit access to
unit from end users.
Other manufacturers’ receivers sound distorted.
It is probably because the Listen transmitter is over-deviated.
See Page 10 for instructions on how to correct this.
LT-800 Stationary Transmitter Troubleshooting
LT-800 Troubleshooting Listen Receivers:
LR-500 Programmable Display Receiver
and LR-400 Display Receiver
Differences in the LR-400 and LR-500
Differences between the LR-500 and LR-400 include: SEEK and
channel UP and DOWN buttons are behind the door on the LR-400
versus protruding through the door on the LR-500. Also, the LR-500 is
programmable. See page 25 for LR-500 programming features. (Other
than these differences, instructions for use of Listen’s LR-400 and
LR-500 receivers and their specifications are identical.)
Preparing Listen Receivers for Use
1Remove the product from the shipping
container and plastic cover. Inspect for physical
damage. See "Technical Service Contacts” (Page 4) if
damage has occurred.
2Check to see if the door is locked. If locked,
use a pocketknife or small screwdriver to unlock the door
locks on the both sides ofthe unit. To unlock the door, rotate
the lock 1/4 turn counter clockwise.
3Open the front access door by gripping the two
tabs with your thumb and index finger.
4Select Battery Type – CAUTION: If you are using
any battery type other than rechargeable Nickel Metal
Hydride (NiMH) batteries, make sure the BATTERY SELECT
switch is in the alkaline position (located in the battery
compartment and labeled BATTERY SELECT, remove batteries
to access this switch). The product is shipped from the
factory in the alkaline position.
To use NiMH batteries, before placing in unit, change
the battery switch to NiMH.
WARNING: Do not place the BATTERY SELECT switch in the
NiMH position when using Non-Nickel Metal Hydride
batteries. The NiMH position will attempt to charge the
batteries. Charging non-Nickel Metal Hydride batteries may
result in physical harm, destruction of property and/or fire.
TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
Listen Receivers: LR-500 and LR-400, Preparing for Use
The LR-400
has channel
UP, DOWN and
SEEK buttons
behind the
door.
The LR-500
has channel
UP, DOWN
and SEEK
buttons
protruding
through the
door.
To unlock door: On
both the right and
left side, unlock by
turning slot
horizontal as shown.
BATTERY SELECT
Switch - With
batteries removed,
use a pen or small
screwdriver to select
the battery type
LR-400 &LR-500 RECEIVERS
productmanual 11x17.qrk 10/11/99 2:43 PM Page 12

TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
Preparing the LT-700 for Use
1Remove the product from the shipping
container and plastic cover. Inspect for physical
damage. See "Technical Service Contacts” (Page 4) if
damage has occurred.
2Check to see if the door is locked. If locked,
use a pocketknife or small screwdriver to unlock the door
locks on the both sides of the unit. To unlock the door, rotate
the lock 1/4 turn counter clockwise.
3Open the front access door by gripping the two
tabs with your thumb and index finger.
4Select Battery Type – CAUTION: If you are using
any battery type other than rechargeable Nickel Metal Hydride
(NiMH) batteries, make sure the BATTERY SELECT switch is in
the alkaline position (located in the battery compartment and
labeled BATTERY SELECT, remove batteries to access this
switch). The product is shipped from the factory in the
alkaline position.
To use NiMH batteries, before placing in unit, change
the battery switch to NiMH.
WARNING: Do not place the BATTERY SELECT switch in the
NiMH position when using Non-Nickel Metal Hydride batteries.
The NiMH position will attempt to charge the batteries.
Charging non-Nickel Metal Hydride batteries may result in
physical harm, destruction of property and/or fire.
5Place Batteries in Unit Place two AA batteries in
the compartment, making note of the battery polarity shown in
the battery compartment, and again verifying that the
BATTERY SELECT switch is switched correctly for your
batteries (see Step 4).
LT-700 Portable Transmitter Preparation
On both the right
and left side,
unlock by turning
slot horizontal as
shown.
_
_
+
+
Top of Unit and Battery Compartment
BATTERY SELECT
Switch - With
batteries removed,
use a pen or small
screwdriver to select
the battery type
20 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-700 Portable Transmitter Specifications
RF Frequency Range:
72MHz: 72.05 - 75.95MHz
216MHz: 216.025 - 216.975 MHz
Transmitter Stability:
50 PPM
Modulation Type:
FM, ±25 kHz wide band,
±7.5kHz narrow band
Frequency Response:
15Hz to 50kHz, within ±3dB
Output Power:
72MHz: 8000uV at 3 meters
216MHz: 20mW
(Max allowed by FCC)
Signal to Noise ratio:
Wide band channels, 60dB
Narrow band channels, 54dB
Antenna:
Uses microphone cable
Available Channels:
72MHz: 17 wide band, 40 narrow band
216MHz: 19 wide band. 38 narrow band
(Modulation is automatically switched when
changing between narrow and wide band channels)
Physical Dimensions:
3”W x 1”D x 5”H
(7.6cm W x 2.5cm D x 13cm H)
Weight:
< 1 lb. (0.45 kg) with batteries
Door:
Channel and ON/OFF buttons are accessible
through the door, lockable
Programmability:
Allows only programmed channels to be tuned
and to be displayed
Power:
Two AA batteries, alkaline or NiMH
rechargeable; external power
connector 8-9 VDC, center positive, <300mA
Battery Charging:
Fully automatic, < 14 hours
Phantom Power:
Included for microphone
Battery Life:
16 hours with high capacity alkaline
8 hours with rechargeable NiMH
Microphone Input:
-55dBm, 50 ohms, unbalanced, tip of 3.5MM
connector
Line Input:
-10dBm, 10k ohms, unbalanced, ring of
3.5MM connector
Audio Processing:
40dB automatic 3-speed dynamic control
with noise gate
Controls:
On/Off/Program/Lockout, Channel UP, Channel
DOWN, Battery Type
Mute Control:
Located on top of unit, LED flashes when
mute is activated
LCD:
Channel, Battery/Charge Status, Program,
Locked, Channel Lock Out
LED:
Red, Constant = ON and/or charged, fast
flash = muted, slow flash = battery low or
charging
LT-700 Portable Transmitter Specifications
LT-700 Transmitter
productmanual 11x17.qrk 10/11/99 2:43 PM Page 13

14 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-700 Portable Transmitter Preparation (cont.), Operation
Preparing the LT-700 for Use (continued)
6Connect the microphone to the microphone jack
on the top of the unit. The unit uses the microphone cable as
an antenna. If you are using the line input, use the special
cable accessory designed for this purpose.
Or, connect optional Line Level Input
Cable – Use an optional Listen supplied line input cable,
or connect as follows:
7Turn the unit on. If it does not turn on by pressing
power button, check to ensure you have installed charged
batteries and that the batteries have been installed with the
proper polarity.
Operating the LT-700 Transmitter
1Make sure the unit is on by opening the access
door and pressing the POWER button.
2Select the channel to transmit on by pressing and
holding the channel UP and DOWN buttons for 3 seconds. The
LOCK symbol on the LCD will go off and the channel can be
changed. Also see “Selecting a Channel to Transmit On”.
Operating the LT-700: Select a Channel (continued)
4At 72MHz, the LT-700 operates on 17 wide
band channels and 40 narrow band channels
(letters = wide band and numbers = narrow
band channels).
4At 216MHz, the LT-700 operates on 19
wide band channels and 38 narrow band
channels (channels beginning with “2” = wide
band, and channels beginning with “1” or “3”
= narrow band channels).
Please refer to the Frequency Compatibility
Tables (Pages 28-31) for specific frequencies
and compatibility with other manufacturers.
4 NOTE: Operating on a narrow band channel will have
less fidelity and more noise.
3Close the access door.
If you choose, lock the door by rotating the
locks on the right side 1/4 turn clockwise,
and on the left side 1/4 turn counter
clockwise. This can be done with a small
screwdriver or pocketknife.
1. Turn POWER on
by pressing
button, turn off
by pressing
again
2.LED should light up
green when ON
3. LCD display
should show
battery level,
channel and
the Listen
logo
Access Door
Closed
On both the right
and left side, lock
door by turning slot
vertical as shown.
TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
The LT-700 has no power.
Make sure the unit has either fully charged batteries or a Listen
approved wall transformer connected to the unit. Open the
door and press the ON button. If this does not work, try a
different set of batteries. Make sure the batteries are installed
properly.
There is no audio.
Make sure the MUTE switch is off. Make sure you have the
microphone plugged all the way in the top of unit. Make sure
you are using a Listen approved microphone. If you're using
the line input, make sure you have connected a line level,
unbalanced input to the "ring" of the connector.
The audio is distorted.
Make sure you're using an approved Listen microphone. Make
sure the line input level is not too high.
There is hum in the audio.
The microphone may be too close to a transformer.
The microphone is low in level.
The microphone must be placed in close proximity to the
person speaking. If this does not work, try using a head-worn
microphone.
There is too much noise.
This is probably due to the fact that the microphone is not close
enough to the person speaking and is picking up background
noise. Try positioning the microphone closer or try using a
microphone that is directional (like a head-worn mic).
There is interference.
Try different frequencies until you find a clear channel. If this
does not work, try a different frequency band (i.e. if you're
using 72MHz, try 216MHz or vice versa). This is accomplished
by returning the equipment to Listen (no charge) and replaced
with alternate frequency band equipment.
I cannot pick up the signal on the receiver.
Check to make sure the receiver and the transmitter are on the
same frequency.
I can pick up the signal on the receiver, but it sounds
like it's not tuned in.
Check to make sure the transmitter and receiver are on exactly
the same channel number/letter.
I'm using another brand of receiver - how do I tell which
channel to use?
Refer to Listen’s Frequency Compatibility Table (included on
Pages 28-31). Either adjust the transmitter or the receiver to a
common channel.
There is not sufficient range.
The LT-700 is a portable transmitter that uses the microphone
cable as an antenna and as such, the range will vary depending
on the location of the receivers compared to the transmitter.
You can only expect 100 feet of effective working area.
It's confusing for users to have 57 channels when
switching between channels.
Use the programming feature of the LT-700 to limit the number
of channels users have access to.
How can I limit access to the batteries?
Use the side door locks.
My batteries are not charging.
Make sure the battery switch is in the NiMH position. Make
sure you have turned the unit’s POWER on initially to charge.
Make sure you have connected an approved Listen charging
transformer. Or if inserted in charging tray, make sure the unit
is ON and is pushed securely into tray. Make sure you use
ONLY NiMH batteries provided by Listen. Never try to charge
alkaline or NICAD batteries.
I want to run the unit from a wall transformer.
Simply plug a Listen approved transformer to the Charge/Power
connectors. Batteries need not be installed, however NiMH will
be recharged if installed, and if the BATTERY SELECT switch is
set to NiMH.
LT-700 Portable Transmitter Troubleshooting
LT-700 Troubleshooting
LT-700 Transmitter
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TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
LT-700 Portable Transmitter, Selecting a Channel
Selecting a Channel Transmit On
Selecting a clear channel to broadcast is important for interference
free broadcasting.
Wide Band Recommendation: If you don’t plan to have other
transmitters (or a limited number) operating in the same area, it is
recommended that you use wide band channels. These are the most
common channels used. Many people own receivers that will
operate on these channels. In addition, wide band channels offer the
best fidelity and the lowest noise. In this case, select one of the 17
wide band channels A through R on the 72MHz system, or one of the
19 wide band channels on the 216MHz system labeled 2A, 2B, 2C,
etc. The best way to select a channel is by trial and error. Try a
channel, if it has low interference and reliable performance, stick to
that channel.
Compatibility with other manufacturers – If you are
using other manufacturer’s receivers with the LT-700, find out their
frequency, then refer to Listen’s Frequency Compatibility Tables
(Pages 28-31) to find the LT-700 channel number or letter that
corresponds with the receiver’s frequency. As much as possible,
Listen has duplicated the wide band channel letters to cover
frequencies of other major brands. However, we recommend
verifying corresponding channel numbers and letters on the tables on
pages 28-31.
If you are using other manufacturer’s receivers and the sound is
distorted, it is probably because the receiver is not designed to handle
the ±25kHz deviation of the Listen transmitter. This can be corrected
by turning the PROCESSOR control knob all the way counter-clockwise
and turning the INPUT LEVEL knob down. Or, contact Listen Technical
Service (Page 4) to adjust the transmitter deviation internally.
Several transmitters operating in the same
environment – For this, you will need to choose your transmitting
frequencies carefully. The following guidelines should be used to
choose channels:
a. If possible, use all wide band channels. These channels
offer better fidelity and lower noise.
b. Select channels that have the highest frequency separation as
possible (see Frequency Compatibility Tables, pages 28-31), to
avoid adjacent channels and interference. Selected channels
should be at least 200kHz apart.
c. Through a process of trial and error select a combination of
channels that offer the lowest interference and highest reliability.
Channel the unit is tuned to
Indicates battery level in 3 stages,
flashes when battery is low along with
flashing red LED
Indicates the unit is in PROGRAM
mode (to enter PROGRAM mode, press
UP and DOWN until the PGM symbol
on the LCD display is shown.)
L/O = Locked Out – while in
PROGRAM mode, L/O shows what
channels are locked in or out
LT-700 Look & Listen™Display Descriptions
18 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-700 Portable Transmitter, Battery Recharging
Charging the Batteries (continued)
4. Install NiMH rechargeable batteries in the battery
compartment, ensuring that proper polarity has been observed.
Note: It is recommended that you only use a Listen charging
transformer. Or, set the LT-700 with NiMH batteries within unit
and powered ON in a Listen Battery Charging Tray.
5. The LT-700 must be powered ON initially to
charge NiMH batteries within unit – Connect the wall
transformer to the LT-700. The unit must be on to charge.
However, once the charger has started, the unit can be turned off.
6. Once the batteries are fully charged, the unit will stop charging
the batteries. Full-charge will be indicated when all the battery
symbol segments are illuminated and the LED near the volume
control is glowing steadily.
7. The unit can be operated while batteries are charging.
_
_
+
+
Top of Unit and Battery Compartment
For charging using a transformer: with NiMH batteries in unit,
plug wall transformer in CHARGING connection and into wall outlet
(as shown). Batteries will be fully charged when red LED shines
solid red. (LED and battery symbol will flash slowly while charging.)
Operating the LT-700 with a Wall
Transformer
1. The unit will operate normally when connected to a wall
transformer.
2. Batteries do not need to be installed in the unit to operate
using a wall transformer.
LT-700 Transmitter
Indicates unit is
locked into channel,
press and hold UP or
DOWN button for 3
seconds to unlock
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TM
LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications subject to change without notice.
16 LISTEN TECHNOLOGIES CORPORATION +1.435.647.0318 1.800.330.0891 Fax: [phone]
Internet: www.listentech.com All specifications are subject to change without notice.
LT-700 Programming
In General: The LT-700 can be programmed to transmit on a limited
number of channels. For applications where users are required to
select a channel (such as classrooms), and you don’t want them to
have to scroll through all of the available channels, this feature is ideal.
If all channels where available, the user could have 57 channels to
select from.
1. Enter PROGRAM Mode:
2. Scroll through channels to lock or unlock
Use the UP and DOWN
channel select keys to scroll
through all 57 channels.
When checking a particular
channel, the L/O symbol on
the LCD will be displayed
when that channel is locked
out. “Locked Out” means
the channel is not available
to the user after the
programmer exits
PROGRAM mode.
Locking into One Channel
Enter PROGRAM Mode (as described to the right), lock all
channels except the channel you want to use.
LED Indicator
Battery Status Icon
LT-700 Portable Transmitter Programming
Steady Red LED = Normal Operation
Slow Flashing = Battery is Low
Slow Flashing while charging = Unit is Charging
Fast Flashing = Mute
To enter PROGRAM mode, open
the access door and press the UP
and DOWN keys simultaneously
until the PGM symbol is displayed
on the LCD display.
To toggle
between
locked out and
not locked out,
press the
POWER button.
On each channel, check to see if
“L/O” is displayed; it means
channel is locked out from the user
3. To exit PROGRAM mode, don’t press a key for 4 seconds.
When the battery is fully charged,
all three segments of the battery
symbol will be displayed, as shown.
The status of the
battery is
indicated by the
battery symbol on
the LCD.
As fewer battery segments are displayed, the
lower the battery level, as shown.
When the batteries are almost fully discharged, the
battery segments and the red LED near the volume
control will blink quickly. When this occurs, less than
5% of the battery life is remaining and the batteries
should be immediately replaced or recharged.
This segment will blink when batteries are low.
TM
LT-700 Portable Transmitter
Unlocking and Locking the Access Door
The front access door can be locked so that the users will not have
access to controls or batteries. To do this, use a pocketknife or small
screwdriver to rotate the locks as shown.
Charging Batteries Using SmartCharge™
1. The LT-700 is unique because it has an automatic battery
charger built in. That means that when the unit is connected to
a wall transformer or placed in a Listen battery recharging tray,
NiMH batteries will be charged within the LT-700. Once
batteries are charged the internal battery charger will
automatically turn off. This prevents overcharging of batteries,
automates the process of charging, and makes it so you don’t
have to remember to unplug the charger.
2. Do not attempt to charge alkaline or any other type of non-NiMH
batteries. Only charge Nickel Metal Hydride (NiMH) batteries
within the LT-700. We recommend that you use NiMH batteries
supplied by Listen.
WARNING: Attempting to charge non-NiMH batteries may
result in physical harm, destruction of property and /or fire.
3. IMPORTANT: To charge NiMH batteries, the BATTERY
SELECT switch must be selected to NiMH. Use a pen or small
screwdriver to the move the switch (located in the battery
compartment directly below the BATTERY SELECT label) to the
proper position.
To unlock: On both
the right and left
side, unlock by
turning slot
horizontal as shown.
To lock: On both the
right and left side,
lock door by turning
slot vertical as
shown.
For only NiMH batteries: set
BATTERY SELECT switch to
NiMH. For all other batteries,
set BATTERY SELECT at
alkaline.
(Continued...)
LT-700 Transmitter
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