Listen LT-700 User manual

User’s Manual
LT-700 Portable Transmitter
Don’t miss a single sound. Listen.
Listen Technologies Corporation
8535 South 700 West, Suite A
Sandy, Utah 84070-2515 USA
Telephone: [phone]
Toll Free (North America): 1.800.330.0891
Fax: [phone]
E-mail: [e-mail]
Listen®and the Listen logo are registered trademarks of Listen Technologies Corporation

Welcome to Listen!
i
Dear Valued Customer,
Thank you for choosing Listen! All of us at Listen are dedicated to providing you
the highest quality products and prompt, efficient customer care. Our products are
manufactured in an ISO-9000 factory that has been independently certified to the
highest quality standards. We stand ready to answer any questions you might have
during installation or in the operation of our products. Should there be any
problems with your Listen products, we are ready to help you in any way we can.
Should you have any comments on how we might improve our products or our
service, we’re here to listen. Here’s how to reach us:
Telephone: [phone]
Fax: [phone]
Toll Free (North America): 1.800.330.0891
E-Mail: [e-mail]
Web: www.ListenTech.com
Thank you... and enjoy your listening experience!
Best regards,
The Listen Team
Listen™ and the Listen Logo are registered trademarks of Listen Technologies Corporation.
LT-700_2004_02_18 © 2004 Listen Technologies Corporation. All Rights Reserved.

Welcome to Listen!
ii
· LT-700-072 (72MHz or 216MHz)
· Warranty Card
· User Manual
LT-700 Package Contents
72 MHz: LT-700-072
216 MHz: LT-700-216
Listen Part Number
See pages 32-33.
Optional Accessories

iii
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Table of Contents
1
Architectural Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Programming Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Charging Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Operation with a Wall Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Supplementary Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Channel Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Listen SQ™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
RF Reception Maximization Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
72 MHz Frequency Compatibility Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
216 MHz Frequency Compatibility Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Compliance Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
FCC Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Table of Contents

Specifications
2
Specifications
Architectural Specifications
The portable FM transmitter shall be capable of broadcasting on 57 channels. The unit shall incorporate a microphone
sensitivity switch. The device shall broadcast on both wide and narrow band channels with a SNR of 80dB or greater.
The device shall have an audio frequency response of 50Hz to 15kHz, ±3dB at 72MHz, or of 50Hz to 10kHz, ±3dB at
216MHz. The device will incorporate a mute switch. The battery door shall be capable of being mechanically locked.
The device shall incorporate an LCD display that indicates channel, battery level, low battery, battery charging, channel
lock ,program mode, channel lock status and RF signal strength. The portable transmitter shall incorporate automatic
battery charging circuitry for recharging of NiMH batteries. The Listen LT-700 is specified.
Specifications
Specification LT-700-072 LT-700-216
RF Frequency Range 72.025 - 75.975 MHz 216.025 - 216.987 MHz
Number of Channels 57 (17 wide, 40 narrow) 57 (19 wide, 38 narrow)
Sensitivity
Frequency Accuracy
Transmitter Stability
Transmission Range
Output Power Less than 10mW Less than 100mW
Antenna
Antenna Connector
Compliance
.6uV typical, 1 uV maximum for 12dB SINAD
RF
±.005% stability 0° to 50°C (32° to 122° F)
50 PPM
FCC Part 15, Industry Canada
3.5mm connector
From 0ft to 50ft(15.2m) -150 ft (45.7m)
Uses microphone cable
continued on next page

Specifications
3
Specifications continued
System Frequency Response 63Hz - 15kHz (± 3dB) 63Hz - 10kHz (±3dB)
System Signal to Noise Ratio
(A-weighted)
SQ enabled: 80dB; SQ disabled 60dB SQ enabled: 80dB; SQ disabled 50dB
System Distortion
Microphone Input
Microphone Sensitivity
Line Input
Phantom Power
Set-up Controls, behind the door
User Controls
Programming
LED
LCD Display
Battery Type
Battery Life (Listen batteries)
Battery Charging (NiMH only)
Power Supply Connector
Compliance
Dimensions
Unit Weight
Unit Weight with batteries
Shipping Weight
Door
Temperature - Operation
Temperature - Storage
Humidity
3VDC
Physical
Environmental
Audio
Indicators
Controls
Power
Unbalanced, tip of 3.5mm connector, (55 dBu nominal,
-32dBu maximum, impedance 21 Ohms)
Unbalanced, ring of 3.5mm connector, (-10dB nominal input level adjustable, +4dBu maximum,
impedance 10k Ohms)
** All system specifications are wireless end-to-end
0 to 95% relative humidity, non-condensing
5.8 oz (164.4g)
1.0 lbs (0.45kg)
Manually lockable. UP, DOWN and power through door,
other controls behind door (see Controls above)
-20° to 50°C (-4° to 122° F)
-10° to 40°C (14° to 104° F)
Two AA batteries, alkaline or NiMH
Mic sensitivity, NiMH/alkaline battery, SQ enable/disable
Unit can be programmed so that only desired channels are displayed to the user; channel selection can
be locked by holding the UP or DOWN button 5 seconds.
Power, mute, channel UP and DOWN
3.9oz (111g)
Three position switch: high, middle and low; 6dB increments
<2% total harmonic distortion (THD) at 80% deviation
2.3mm OD by 0.7mm ID, barrel type connector. 7.5VDC, center positive 300mA. Drop in contact points
for use with Listen charging cases.
UL Listed
3.0 in x 1.0 in x 5 in WxDxH (7.6cm x 2.5cm x 13.cm)
Fully automatic, 14 hours
20 hours alkaline (LA-361), 10 hours NiMH rechargeable (LA-362)
Red, illuminates when unit is on. Flashes when batteries are low,
or to indicate charging. Flashes 2x when muted
Channel, lock status, programming
Specification LT-700-072 LT-700-216

Quick Reference
4
Quick Reference
LT-700 Front
3.5mm Input Jack
A Listen microphone or line
level cable connects here.
MUTE / TALK switch
(more information on page 5)
Power Switch
Press PWR switch to turn unit
on. Press and hold to turn
unit off. When in PROGRAM
mode, this switch is used to
toggle the lock out (L/O)
mode for a channel.
Press and hold both buttons for 5 seconds to enter PROGRAM
mode. The PGM icon will appear in the display. To exit PROGRAM,
let unit sit idle for 5 seconds.
Use UP and DOWN buttons to select a channel.
Press and hold either button for 5 seconds to
lock the channel. Press and hold either button
again to unlock.
Look & Listen Display™
The display shows level, channel,
battery status, PROGRAM mode,
whether a channel is locked, and
whether a channel is locked out
from selection (PROGRAM mode).
See close-up on page 6.

Quick Reference
5
Quick Reference
LT-700 Inside Access Door
Mic Sensitivity Switch - it arrives set at MID, which will
work for most microphones. If your mic level is too low,
change the switch to HI; if the level is too high, switch to
LO. (see page 8 for more information)
Battery Select Switch - place in NiMH position ONLY if you
are using Nickel Metal Hydride batteries, otherwise, leave it
in the Alkaline position.
SQ Switch: shipped in the ON position, use a screwdriver
or pen to slide to the OFF position if needed. You should
turn SQ off if you are using any non Listen receiver or older
Listen receiver that does not have the SQ feature. (see
page 20 for more information)
Mic Sensitivity
Switch SQ Switch
Battery Select
Switch
3.5mm Input Jack
A microphone or line level cable connects here.
LED indicators:
Steady Red: Normal operation
Slow Flashing: Battery is low
Slow Flashing while charging: Unit is charging
Fast Flashing: Mute
MUTE / TALK switch - this mutes the mic
only and not the line input when in the mute
position.
LT-700 Top of Unit
A Note on Charging NiMH Batteries
If you are using NiMH batteries in any Listen
product, you should allow adequate time
for the charger (charging case or LA-202)
to complete a full charge cycle on the
batteries. This takes about 13 hours.

Quick Reference
6
Quick Reference
LT-700 Look & Listen™ Display
When dots are illuminated, the microphone
is active. If this display does not appear,
the microphone is muted.
Indicates the currently
tuned channel
Indicates the unit is in PROGRAM mode
(see next page). To enter PROGRAM
mode, press and hold the UP and DOWN
keys until the PGM icon appears in the dis-
play. To exit PROGRAM mode, let the unit
sit idle for 5 seconds. If the padlock icon is visible, the channel is
locked. Press and hold either the UP and
DOWN button for 5 seconds to lock or
unlock.
When in the PROGRAM mode, L/O
indicates whether a particular channel
is locked out.
Battery level indicator. The indi-
cator flashes, along with the red
LED on top of the unit, to alert
you when the battery is low and
needs to be charged or
changed. (see information
below)
All three segments showing:
The batteries are at 50% or
greater capacity.
One segment showing:
Your batteries less than 25% capacity. When
this segment begins flashing along with the
LED on top of the unit, you should immedi-
ately change your batteries or recharge them
(if using NiMH batteries).
Two segments showing:
The batteries are at 25-49%
capacity.
LT-700 Battery Indicator

Setup Instructions
7
LT-700 Setup Instructions
Remove the product
Remove outer packaging and plastic cover. Inspect for physical damage. If damage is aparent,
please contact Listen Technologies Corporation technical support
for assistance. See page 29 for contact information.
Open the front access door
If locked, use a pocketknife or small screwdriver to unlock the door
locks on both sides of the unit. To unlock the door, rotate the lock
¼ turn counterclockwise.
Grip the two tabs with your thumb and index finger and pull the
door downward. Do NOT place batteries in the unit yet.
Select Battery Type
See diagram on page 8. You have two choices: NiMH and Alkaline.
The unit is shipped with the switch in the Alkaline position. Use a
pen or small screwdriver to select the battery type.
CAUTION: If you are using any battery type other than
rechargeable Nickel Metal Hydride (NiMH) batteries, make sure the
BATTERY selection switch is in the alkaline position.
LockedUnlocked
WARNING: Do not place the BATTERY switch in the NiMH position if you are not using
Nickel Metal Hydride Batteries. The NiMH position will attempt to charge any batteries
in the unit, even if they are not the proper type. Charging non-Nickel Metal Hydride
(NiMH) batteries will result in physical harm, destruction of property and/or fire.

Setup Instructions
8
LT-700 Setup Instructions continued
Set SQ switch
The SQ switch is inside the battery compartment next to the Battery
Select switch. The unit is shipped with SQ in the ON position. To turn it
off, use a small screwdriver or pen to slide the switch to the OFF position
(to the right). See page 20 for more information on SQ.
Set Mic Sensitivity Switch
The microphone sensitivity switch is located inside the battery compart-
ment, to the left of the BATTERY selection switch. The LT-700 is shipped
with this switch in the center (MED) position. Listen recommends the
following settings for our microphones. If you are using a microphone from
another vendor, you may need to experiment with different settings.
Part # Description Setting
LA-261 Lavalier Microphone MED
LA-262 Over-the-Head Microphone MED
LA-268 Over-the-Ear Microphone MED
LA-270 Noise Cancelling Microphone MED
LA-277 Confrerence Microphone MED
LA-272 Over-the-Head Mic w/Earphone MED
LA-273 Over-the-Ear Mic w/Earphone MED
LA-278 Behind-the-Head Microphone MED
LA-274 Handheld Microphone HI
LA-276 Collar Microphone HI
NOTE: If the setting is too low for
the microphone in use the audio will
be faint. If the setting is too high for
the microphone in use the audio will
be distorted.
Battery Select
Switch
Mic Sensitivity
Switch SQ Switch

Setup Instructions
9
LT-700 Setup Instructions continued
Place 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 in the cor-
rect position for the batteries you are using. (ALK should be selected for all battery types
other than NiMH).
NOTE: Listen uses 1800mAh (milli-Amp-hour) constant current NiMH (Nickel Metal
Hydride) batteries. These may be purchased from your Listen dealer (ask for part number LA-
362).
Connect the Microphone
The microphone jack is located on top of the unit. The LT-700 uses the microphone cable as
an antenna for transmitting.
LA-268 Over-the-Ear Microphone

Setup Instructions
10
LT-700 Setup Instructions continued
Optional - Connect the Line Input Cable.
This cable allows you to connect a TV, CD player or other equipment to
the LT-700. To do this, you must order the Listen LA-263 Line Input
Cable (it is not included with your unit). This cable allows you to con-
nect both a microphone and line input to the jack on top of the LT-700.
See the diagram below for connection information. You can use the
microphone and the line input at the same time. Please note that the
MUTE switch mutes only the microphone; the line source will continue
transmitting when the switch is in the MUTE position.
If you prefer to make your own cable for connection of mic and line inputs,
connect shown in the following diagram:
Stereo-Red
Mono-White Video-Yellow

Operating Instructions
11
LT-700 Operating Instructions
Make sure the unit is on
When you press the power button, the LED on top of the unit will be illuminated and the
LCD display will be visible.
Select the channel for transmitting
Please refer to Channel Selection on pages 18-19 for guidelines on choosing an interference-
free channel.
To select a channel, press either the channel UP or DOWN button until the display reads the
channel you want. To lock your selection, press and hold the UP or DOWN button for 5 sec-
onds. When locked, the small padlock icon will be visible on the display. Press and hold
either button again to unlock.
72MHz Units
The LT-700-072 operates on 17 wide band channels and 40 narrow band channels. Channels
represented by letters in the display (i.e. A) are wide band channels; channels represented by
numbers are narrow band channels.
216MHz Units
The LT-700-216 operates on 19 wide band channels and 38 narrow band channels. Channels
beginning with a “2” are wide band channels and channels beginning with a “1” or “3” are nar-
row band channels.
Listen recommends using wide band channels whenever possible, as they are not as noisy as
narrow band channels.
Refer to the Frequency Compatibility tables (pages 22-25) for specific frequencies and compati-
bility with other manufacturers. Also refer to pages 18-19 for more information on channel
selection.

LT-700 Operating Instructions continued
Close the Access Door
Lock it if desired by turning the locks on the side of the unit to the vertical position. See
diagram on page 7.
Using the red MUTE / TALK switch on top of the unit
The red mute/talk switch on top of the unit is a handy way to “turn off” the audio from the
microphone. Slide the switch to the mute position and the microphone audio is muted.
When the microphone audio is muted, the LED on top of the unit flashes rapidly. Slide the
switch back to the talk position and the microphone audio will return to the transmission. If
you are using line level audio, it will not be effected by the mute/talk switch.
Operating Instructions
12
LT-700 Shown in the TALK position

Programming
13
LT-700 Programming Instructions
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 or language interpretation),
and you don’t want them to have to scroll through all of the available channels, this feature is
ideal. You can set up the LT-700 so that only the channels they need to use are available for
selection with the UP and DOWN buttons.
Enter PROGRAM Mode
Press and hold the UP and DOWN keys simultaneously until the PGM symbol is displayed (see
the Look & Listen™ Quick Reference on page 6).
Scroll Through Channels to Lock or Unlock
Use the UP and DOWN channel select keys to scroll through all available channels. If the
L/O symbol appears with a particular channel’s indicator, this means that particular channel
will not be available for selection by the user. To toggle a channel between locked out and
available, press the POWER button.
To exit PROGRAM mode
Allow the unit to sit idle (don’t press any buttons) for 5 seconds. The LT-700 will exit the
PROGRAM mode and the PGM icon will disappear.

LT-700 Charging Batteries
The LT-700 and all Listen receivers are unique because they have
SmartCharge™ chargers built in. When any of these units are connected
to an LA-202 wall transformer or dropped into a Listen charging case,
NiMH batteries will be charged.
To charge the batteries using the LA-202 wall transformer, plug the trans-
former into the jack marked “PWR/CHG” on the side of the unit. The
unit can be operated while the batteries are charging.
To charge the batteries using a drop-in charger, simply place the unit into a
slot in the charger and connect the charger to power. Make sure the unit is
fully seated in its slot.
One of several charging cases available from Listen. Check the Listen web-
site for more details.
SmartCharge™ uses a pulse charging, which greatly extends the life of
Nickel Metal Hydride (NiMH) batteries. The entire charging process takes
about 13 hours. Listen recommends that you allow the charger to complete
its full cycle every time for maximum battery life.
IMPORTANT: In order to charge NiMH batteries, the BATTERY SELECT switch in your
Listen product must be set to the NiMH setting. Use a pen or small screwdriver to move the
switch (located in the battery compartment) to the proper position.
Charging Batteries
14
Connect LA-202
here and plug it
into an AC wall
outlet.
IMPORTANT: DO NOT ATTEMPT TO CHARGE ANY TYPE OF BATTERY OTHER THAN NiMH (NICKEL METAL
HYDRIDE) with your Listen equipment. Alkaline batteries may explode when connected to a
charger. Other risks of charging non-NiMH batteries include destruction of property or fire.

Charging Batteries
15
LT-700 Charging Batteries continued
During the charge cycle, the red LED on top of the Listen product will flash slowly. When
charging is completed, the LED will turn off. It is not necessary to unplug the charger; howev-
er, if you unplug the unit from the charger and then plug it back in, it will begin the 13-hour
charge cycle over again.
When not using the LT-700, it is recommended to leave the unit on the charger. The charger
provides a “maintenance” charge that keeps the battery at 100%. If the unit is not on the
charger, the battery will lose up to 20% of its charge per month.
NOTE: Listen uses 1800mAh (milli-Amp-hour) constant current NiMH (Nickel Metal
Hydride) batteries. These may be purchased from your Listen
dealer (ask for part number LA-362).
One of several charging cases
available from Listen. See
www.ListenTech.com for more
options.
LA-311 - 16-unit Drop In Charging Case shown

LT-700 Wall Transformer Operation
The LT-700 will operate normally when connected to a wall transformer. Use Listen part number
LA-202, available from any Listen dealer. Connect the wall transformer to the jack on the side of
the LT-700 marked “PWR/CHG” and plug the wall transformer into a grounded AC outlet.
You do not need to have batteries installed in the LT-700 to operate it with a wall transformer.
NOTE: If batteries are in the unit ensure
that the battery selection switch is set
properly as shown on page 5. Please
review the information on page 14 for
important information regarding battery
type and charging.
Wall Transformer Operation
16