Computer programs for use in data base management of clients' information such as names, addresses, phone numbers, services available, states of equipment, states of use of services, and the like; computer programs for use in data base management of clients' negotiation states; computer programs for use in answering clients' complaints; computer programs for use in calculating the charges of the services used by clients; computer programs for use in managing the receipt of charges corresponding to the services used by clients; computer programs for use in managing bookkeeping information; computer programs for use in accounting management; computer programs for use in database management for personnel management; computer programs for use in salary information management; computer programs for use in inventory information management; computer programs for use in telephone exchanges; computer programs for use in telephone exchange control; computer programs for use in the design of other computer software; computer programs, namely, software testing tools; computer application middleware for use in connection with the foregoing, magnetically encoded credit cards, intergrated circuit credit cards