Talk-Through
Level Dependent Functionaility, commonly referred to as €œtalk-thru,€� is a means of allowing safe audio sounds to bypass the individual hearing protection while still protecting against harmful noises. This can be accomplished with a proprietary digital audio circuit integrated into the headset. A microphone will receive sounds outside its headset and transmit those to a speaker inside the headset. This Level Dependent Digital Audio Circuit easily senses noise levels above the desired threshold and compresses each to a safe decibel level or amplifies weak sounds to an audible level.

Compression vs. Clipping
3M has incorporated compression technology to remove the €œclipping€� effect heard in common talk-thru systems. €œClipping€� can result in missing the first syllable of important commands. This technology resolves that issue and dramatically improves speech intelligibility.

Fail Safe
ComTac External Communication (i.e. radio or intercom) and €œtalk thru€� are completely independent of one another. In the unlikely event of electronic failure or battery depletion, external communications will continue to function.

Environmental
-MIL STD 810F, Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests
-Submersion: 3 feet, 30 minutes, salt-water-survivable

EMI
-MIL STD 461E, Department of Defense Interface Standard, Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment
-CS1 14, RE101, RE-102-4, RS101 and RS103 Requirements

Noise Reduction Ratings(NRR)
(per ANSI S3.19-1974; NAVLAP Certified - Tested internally at 3M€s NAVLAP-accredited facility)
-COMTAC III ACH (headband version, standard foam cushion): NRR 23 dB
-COMTAC IV: Classic Foam Eartip - NRR 30 dB; UltraFit Reusable Eartip - NRR 18 dB