The invention relates to a bag system for the cryopreservation of body fluids, that is blood, bone marrow or umbilical cord blood, the parts of the bag system being sterilized, and separable from one another, wherein liquids which permit andor assist cryopreservation are located in the bag system andor may be introduced into the bag system in a sterile form. The housing also has means, such as an ear hook, for fastening the communication unit to the head of a user. The equalization coefficients for the equalizer are adapted based on the received signals, and on the phase corrected error, and the adapting is inhibited according to the inhibit signal. The invention is suited for use with the clearing of loose debris in and around a typical construction site.