Abstract: An in-line coupling circuit for a POS terminal, includes a coupling section connected in a communication line and electrically connecting the POS terminal to the communication line. The in-line coupling circuit further includes a regeneration error check circuit for monitoring signals transmitted from and received into the POS terminal and generating an abnormal detection signal when a specified character data included in the received signal and indicating the end of a data frame is not generated from the POS terminal and a reporting circuit for generating a defective code inherent to the POS terminal in response to the abnormal detection signal and transmitting the defective code through the communication line.

Abstract: A sales data registration and payment settlement apparatus includes a number of register terminals for registering sales data of each article to be to be purchased by a customer, and for transmitting the sales data and total sales amount data for each customer to an electronic cash register (ECR) located away from the register terminals. The ECR includes a number of memories for storing data, transmitted from the register terminals when the sales related data for each customer is fully compiled, a printer, and a control unit for driving the printer on the basis of the sales data and total sales amount data for each customer, so that these data items are printed on a receipt. A register terminal associated with each customer arriving at the ECR is designated by way of corresponding call keys on the ECR.

Abstract: The display apparatus includes a first display unit having dot display elements arranged in a matrix of m columns.times.n rows, a second display unit having n segment display elements arranged to have a predetermined pattern, and a display drive circuit to drive the first and second display units. This display drive circuit has a control circuit which generates display data to designate the character to be displayed in each display region in the first and second display units and which sequentially activates the display regions in the first and second display units, and a drive circuit which supplies m.times.n dot data corresponding to the display data from the control circuit to the dot display elements in each of the display regions of the first display unit and which also supplies predetermined n dot data among these m.times.n dot data to the segment display elements in each of the display regions in the second display unit.