Abstract: A weather resistant sound attenuating communications headset of modular construction includes two ear cup modules, a microphone boom module, a head band module, a headband cable module, and a termination cable module. The modular construction allows easy replacement of modules as well as selected components of the modules under field conditions without the need for tools. Replaceable water resistant thin film membranes are employed to provide weather protection as well as hygienic protection for the microphone, speaker and amplification electronics. The thin film membranes which cover areas which come into intimate contact with the wearer are easily replaceable under field conditions. Thus a headset that is shared by more than one user can be hygienically cleansed by simple replacement of the microphone and ear cup membranes.

Abstract: A helmet is supplied with a personal alarm safety system (PASS) that detects the absence of motion by the wearer. This usually indicates that the user is unconscious or otherwise incapacitated. Also in the helmet is an automatic activation means which turns on the PASS system as soon as the wearer puts on the helmet. Other features such as visual alarm and inactivation means are included in the preferred embodiment.

Abstract: A microphone circuit control mechanism which is utilized to control the output of a microphone (20) disposed in a breathing mask (12) the microphone circuit extending to a communications device (22) and wherein the microphone circuit control mechanism includes a switch (86) in the microphone circuit, which switch can be toggled between "on" and "off" states in response to a drop in pressure within a pressure sensing chamber (44). The switch (86) is a single-pole double-throw magnetic reed switch which is disposed within the pressure sensing cavity (44), which cavity is in a demand regulator (14). The regulator includes a valve (27) capable of admitting air under pressure into the pressure sensing chamber when required. The magnetic reed switch (86) is toggled in response to movement of a magnet (112) carried by a portion (64) of a valve operating means (30) which portion moves in response to a drop in pressure in the sensing chamber (44).