ČSN EN 352-9

This document is applicable to earplugs supplemented by a safety-related audio input. The audio signal can be transmitted by electrical input or other communication like Bluetooth1. It specifies requirements on construction, design, performance, marking and user information related to the inclusion of the safety-related audio input. Earplugs with safety-related audio input are designed to provide speech information and warning signals, while providing attenuation of external sound. They may be selected for use in a number of different environments, for example in air traffic communication, in the police forces, in the broadcasting and entertainment industries.