It is known to provide two-way communication devices or intercoms for a wide variety of uses and applications, but generally they allow communication between two parties across a secure barrier. For example, these devices find application at entry points to homes and flats, in banks where they facilitate communication between bank tellers and customers and in public telephones. By virtue of their very application, two-way communication devices are usually located in public places. Consequently, they are required to be vandal proof and weatherproof.
Conventional two-way communication devices typically comprise loudspeakers, microphones and switches housed within a robust outer casing having apertures in the front face to allow sound waves to enter and leave the device and to locate the switches. Often, attacks by vandals on these devices involve objects being pushed through these apertures to damage or destroy the loudspeaker and microphone diaphragms or to jam the switches. Other attacks can take the form of various liquids such as chewing gum, vomit or super glue introduced through the apertures causing a variety of malfunctions.
USPTO Backgrounds
USPTO Backgrounds