The Lectrosonics IFB system virtually guarantees an interference-free means of directing on-camera talent. The transmitter can transmit in 256 different UHF frequencies separated by 100kHz steps ensuring there is no interference with other wireless devices – a common problem with other devices, especially in studio or live event situations. Fed by either a signal from an intercom system or by a direct mic, the transmitter has a range of over 1/4 mile and its noise reduction features plus high-end processing provides a very high quality audio feed to the talent.

Other features include automatic squelching of jarring audio tones; rugged, compact construction; wireless earbud, and long life battery consumption.

Operating Frequencies:
Frequencies (Channels per block):
Channel Spacing:
Spurious & Harmonic Suppression:
4 nW at freq. below 1 GHz
Frequency Stability: Temperature Stability: Channel Selection: Pilot Tone: Modulation:
Audio Response: Audio Compressor: RF Power Output: Output Impedance: Audio Input Levels:
Audio Input Config: Audio Input Impedance:
Gain Control Range: Audio Input Jack: Input Power: Power Input Jack: Indicators:
Front panel controls:
Rear panel controls: Weight: Size:
Specifications subject to change without notice.
Block 21 Block 22 Block 23
Block 24
537.600 – 563.100 563.200 – 588.700 588.800 – 607.900 614.100 – 614.300 614.400 – 639.900
256 100 kHz 1 uW at freq. above 1 GHz
±.002% (20 ppm) @ 25° C
±.005% (50 ppm) from -30° C to +50°
Block 25 Block 26 Block 27 Block 28 Block 29
640.000 – 665.500 665.600 – 691.100 691.200 – 716.700 716.800 – 742.300 742.400 – 767.900
(0.1 MHz)
Momentary pushbutton switches, TUNE Up and Down
29.997 kHz
FM, ±20 kHz deviation
100 Hz to 10 kHz, ±1 dB, -3dB (system response)
2to1
250 mw (nominal)
50 ohms
+4 dBu, -6 dBu, and -40 dBu, dry inputs, +/-50Vdc max,
rear panel selectable for Line, Mic, RTS 1, RTS 2, and Clear Comm
Balanced and Unbalanced, rear panel selectable for Line, Mic. RTS 1, RTS 2, and Clear Comm
Greater than 2 K balanced, greater than 1 K unbalanced at any gain setting
43 dB, Semi-log Rotary control Standard XLR female connector 12 to 14 VDC typical, 250 ma. max.; Max. Input Range 11 to 18 VDC Coax type, locking LZR RL26AE
LED for -20 dB modulation LED for 0 dB modulation 4 Digit 7-segment LED displays for frequency and power on with adjustable brightness
Audio Level rotary knob Power OFF-TUNE-XMIT, 3 position slide switch TUNE Up momentary pushbutton switch TUNE down momentary pushbutton switch
Mode Select, 4 section DIP switch 9 oz. 5.25″ long (including connectors) x 3.25″ wide x 1.25″ high