Abstract: An activity based time accounting system consisting of a plurality of personal data collection devices (PDCD's) which are carried by selected users or workers during a predetermined use period, a central storage and processing facility (SPF) for receiving and storing each of the PDCD units in electrical interconnection during other than said use periods, and circuitry in said PDCD units for recording time accounting data for each of the selected users during each use period; and including collection circuitry for gathering all PDCD unit data during the other than said use periods for compilation and transmission for processing with business accounting software.