The telephone and signal alarm TWIN-EExII is an explosion-protected, opto-acoustic signaling device specifically developed for use in explosive industrial environments – both indoors and outdoors. It combines the functions of a telephone secondary alarm and a signal alarm in a robust, die-cast aluminum enclosure with a transparent polycarbonate cover. A slide switch allows switching between both modes: As a telephone secondary alarm, it is activated by ring voltage and signals incoming calls via a loud multi-tone alarm and a powerful strobe light. In signal alarm mode, it generates acoustic and optical signals by connecting to the 230 V mains. The device features IP66 protection rating, ensuring dust- and water-tight conditions, and is designed for use in Zone 1 and Zone 2 according to Group II. The integrated telephone ring relay function enhances visibility in noisy environments and ensures reliable alarm transmission. The operating temperature ranges from -20 °C to +40 °C, enabling broad applicability in various industrial environments.