Designed for a variety of portable assistive listening applications, the LT-700 Portable Display RF Transmitter delivers the highest level of performance for all needs. Whether transmitting voice or music, the LT-700 offers a clear, reliable signal for use in environments without an installed assistive listening system. Wireless audio is easily and clearly picked up by any of our Listen Portable receivers, allowing you to meet your needs easily and effectively. From outdoor events to classrooms, factory tours to training spaces and more, the LT-700 is the ideal portable transmitter for nearly any setting.

Note: for use in Australia


One (1) LT-700-150 Portable Display RF Transmitter (150 MHz)
One (1) Quick Reference Card


  • Transmits up to six (6) channels of audio simultaneously on the 150 MHz band
  • Offers a choice between 32 different channels for flexibility and ease of setup
  • 80 dB signal-to-noise ratio provides superior audio quality
  • 100% digital signal output ensures a reliable connection to any and all receivers in use
  • Compatible with standard AA alkaline and NiMh rechargeable batteries
  • Easy-to-read Look & Listen (TM) LCD display with battery level, selected channel, and programming information
  • Built-in SmartCharge (TM) prevents batteries from overcharging
  • Mic and/or line-level inputs
  • Mute switch
  • Limited lifetime warranty with Listen Technologies’ hassle-free support
Configurations & Architectural Specs

Architectural Specs

The portable RF transmitter shall be capable of broadcasting on 32 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). 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 device shall be able to enable companding. The unit shall operate off of two (2) AA batteries; alkaline or NiMH. 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-700-150 is specified.

Product Specifications
Specification LT-700-150


Frequency Response 50 Hz - 15 kHz (±3 dB)
Signal-to-Noise Ratio SQ enabled 80 dB, SQ disabled 60 dB
Distortion < 2% total harmonic distortion (THD) at 80% deviation
Microphone Input Unbalanced, tip of 3.5mm connector, -20 dBu nominal, -30 dBu maximum, impedance 21 ohms
Microphone Sensitivity Three position switch: high, middle, and low; 6 dB increments
Microphone Power 3VDC 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


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


Frequency Range 150.8000 MHz - 152.3500 MHz
Number of Channels 6 wideband, 26 narrowband
Frequency Accuracy ± .005% stability 32 to 122º (0 to 50ºC)
Antenna Type Uses microphone cable
Transmitter Stability 50 PPM
Transmission Range up to 45.7m (150 ft.)
Antenna Connector 3.5 mm connector
Output Power 10 mW maximum
Number of Simultaneous Transmitters Six (6)


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
Battery Type Two (2) AA batteries, alkaline or NiMH
Battery Life 8 hours alkaline (LA-361), 8 hours NiMH rechargeable (LA-362)
Battery Charging Time Fully automatic, 13 hours
Compliance RoHS, WEEE, UL, PSE, CE, CUL, TUV, CB compliant


Width 3.00 in. (7.6 cm)
Height 5.00 in. (13.0 cm)
Depth 1.00 in. (2.5 cm)
Color Dark Grey with white silk screening
Unit Weight with Batteries 5.8 oz. (164 g)
Shipping Weight 1.0 lb. (0.45 kg)
Weight 3.9 oz. (111 g)
Door Manually Lockable (on sides). Up, down, and power buttons through door


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


Safety C-Tick
Used With
Q What is the range of the LT-700-150 portable transmitter?
A Line of site up to 45.7 m (150 ft.).
Q Does the LT-700-150 provide phantom power?
A Yes, 3VDC for electret condenser microphones.
Q Will the LT-700-150 portable transmitter work for two-way communication?
A No. However, Listen does recommend ListenTALK a two-way system for tour group applications where talk-back communication modes are available.
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.
Q How long do the batteries last on the portable transmitter?
A Alkaline batteries last 15 hours; NiMH rechargeable batteries last 8 hours (72 MHz & 216 MHz).
Q Can I have multiple LPT-T216 transmitters operating in one facility?
A Yes. Multiple Channels and power settings enable multiple LPT-T216 transmitters to operate within the same facility even in adjacent rooms. However, when multiple transmitters are being used, they will need to transmit on different channels or have adequate distance between the transmitters so they do not interfere with each other. For further information, please refer to the quick setup guide.
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