Abstract: A coupling circuit for coupling a printer to a meter permits single line digital printout of metered data in response to operation of a manual switch. Printing is initiated when a bistable occupies one state and a print command is produced by the meter indicating that a stable voltage has been detected by the meter. That bistable state is produced by manual operation of a switch, such operation also triggering a hold unit within the meter to hold the stable reading for a period permitting data to be shifted to the printer and for printing to occur. While printing and paper advance is under way, the printer delivers a busy signal to the bistable to change its state. Subsequent state reversal can then only take place on manually operating the switch once again. In this way only a single line of print is achieved on command. The particular logic arrangement described prevents erroneous printing of lines of data in response to switch contact bounce.