The PCM/ECM and the SMARTRA communicate by dedicated line. During this communication of PCM/ECM and SMARTRA, the K line of PCM/ECM cannot be used for communication. The PCM/ECM controls the communication either to SMARTRA or to other devices(e.g. scanner) on K line by switching of a multiplexer and specific communication procedures. The multiplexer is a part of PCM/ECM H/W.