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The Listen LT-700 Portable Display RF Transmitter is used to wirelessly broadcast audio for a variety of portable applications. Whether its voice or music, you can broadcast your audio to everyone in the audience without having to carry a microphone or be plugged into a wall. The LT-700 is excellent for factory tours, outdoor events, wireless microphone applications, classrooms, training, or personal use - anywhere you need to amplify sound, but don't have (or want) an installed system. With the many features of the LT-700, portable transmission has never been easier for users!

This product is approved by the FCC for use in the US. Please note that they cannot be used in all countries. Check with your local government or specific regulation with regard to broadcast frequency in your specific country. Note: FCC rules limit the use of this product to assistive listening.


One (1) LT-700 Portable Display RF Transmitter
One (1) Owner's manual (72 MHz)


  • Superior Audio Quality - 80 dB signal-to-noise ratio, setting the industry's sound quality standard
  • A choice between 57 channels, complete antenna and accessory options make Listen products ideal for a wide range of applications
  • Look & Listen™ LCD shows channel, battery status, and programming information
  • 100 % Digital - Listen receivers are digitally-tuned so transmission won't drift; assurance that when you select a channel, it stays on the channel
  • Transmit up to six (6) channels simultaneously on 72 MHz
  • Uses standard alkaline or NiMH batteries
  • Transformer charging plug or drop in charging contacts
  • Built in SmartCharge™ won't allow batteries to overcharge. Charging circuitry is conveniently built into Listen's LT-700 Transmitter; never worry about unplugging a transformer at a certain time
  • Mute switch
  • Mic and/or line level inputs
  • Limited Lifetime Warranty with hassle-free support


LT-700-072 Portable Display RF Transmitter (72 MHz)
LT-700-216 Portable Display RF Transmitter (216 MHz)
LT-700-863 Portable Display RF Transmitter (863 MHz)


Architectural Specs

The portable RF display 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 80 dB or greater. The device shall have an audio frequency response of 50 Hz to 15 KHz, ‘±3 dB at 72 MHz, or of 50 Hz to 10 kHz, ‘±3 dB at 216 MHz. 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, and RF signal strength. The portable transmitter shall incorporate automatic battery charging circuitry for recharging of NiMH batteries, with the ability to charge via a wall transformer or drop in charging case. The Listen LT-700-072 or LT-700-216 is specified.

Specification LT-700-072


Frequency Response 50 Hz - 15 kHz (±3 dB)
Signal-to-Noise Ratio SQ enabled: 80dB; SQ disabled 60dB
Distortion <2% total harmonic distortion (THD) at 80% deviation
Microphone Sensitivity Three position switch: high, middle, and low; 6db increments
Microphone Input Unbalanced, tip of 3.5 mm connector, -45 dBu nominal input level, -30 dBu maximum, impedance 20k Ohms
Microphone Power 5VDC Bias
Line Input Unbalanced, ring of 3.5mm connector, -10 dbu nominal input level, -3 dbu maximum, impedance 10K ohms


User Controls Power, mute, channel UP/DOWN, Mic sensitivity, NiMH/alkaline battery, SQ enable/disable
Programming Channel Lock out,Channel lock


LEDs Red, illuminated when unit is on. Flashes when batteries are low, or to indicate charging. Flashes when muted
LCD Channel Designation, lock status, signal strength indication, battery life, RF Power


Frequency Range 72.025 - 75.950 MHz
Number of Channels 17 wide band, 40 narrow band
Number of Simultaneous Transmitters 6
Frequency Accuracy ± .005% stability 32 to 122º (0 to 50ºC)
Transmitter Stability 50 PPM
Transmission Range From 0 to 150 ft. (45.7 m)
Output Power Less than 10mW
Antenna Type Microphone cable
Antenna Connector 3.5 mm connector


Battery Type Two AA batteries, alkaline or NiMH
Battery Charging Time Fully automatic, 13 hours
Power Supply I/P 120VAC; O/P 7.5VDC 250 mA; Drop in contact points for use with charging cases. Power supply not included (LA-208)
Power Supply Connector 2.3mm OD by 0.7mm ID, barrel type connector 7.5 VDC, center positive <250mA. Drop in contact points for use with Listen charging cases
Compliance RoHS, WEEE, UL, PSE, CE, CUL, TUV, CB compliant
Battery Life 15 hours alkaline (LA-361), 15 hours NiMH rechargeable (LA-362)


Height 5.00 in. (13.0 cm)
Width 3.00 in. (7.6 cm)
Depth 1.00 in. (2.5 cm)
Color Dark Grey with white silk screening
Weight 3.9 oz. (111 g)
Unit Weight with Batteries 5.8 oz. (164 g)
Door Manually lockable, controls accessible through doors
Shipping Weight 1.0 lbs. (0.5 kg)


Temperature - Operation 14 to 104º F (-10 to 40º C)
Temperature - Storage -4 to 122° F (-20 to 50° C)
Relative Humidity 0 to 95% relative humidity, non-condensing


RF FCC Part 15, Industry Canada

Q Can I have multiple transmitters operating in one facility?
A Yes. You can have multiple transmitter operating in one area on different channels, however more than one transmitter cannot be used on the same channel.
Q Can I use a line source with the portable transmitter?
A Yes. Listen offers the LA-263, a mic/line input cable for this use (72 MHz).
Q Does the LT-700 provide phantom power?
A Yes, 3VDC.
Q Will the LT-700 portable transmitter work for two-way communication?
A No. However, Listen does not recommend a two-way system for tour group applications. A two-way system means that everyone hears every sniffle, cough, comment etc. The tour guide loses control of the tour and the tour becomes unproductive.
Q How long do the batteries last on the portable transmitter?
A Alkaline batteries last 15 hours; NiMH rechargeable batteries last 15 hours (72 MHz & 216 MHz). With 863 MHz, Alkaline batteries last 8 hours and NiMH rechargeable batteries last 8 hours.
Q What is the range of the LT-700 portable transmitter?
A Line of site up to 150 ft. (45.7 m) for both 72 MHz and 216 MHz. Line of site up to 200 ft. (60.9 m) with 863 MHz.