| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a two-way communication system performing two-way communication between a host apparatus and a device by a compatible mode and a nibble mode via a parallel cable, and notifying the host device about a state from the device unit such as a printer only when a user requires it. <P>SOLUTION: The host device 2 has a setting means 2b setting permission/forbiddance of state confirmation requirement to the device unit 1. When the state confirmation requirement is set to the permission by the setting means 2b, the host device 2 transmits the state confirmation requirement to the device unit 1 in preset timing in time of a control communication mode, and changes over the mode to a response communication mode. In time of the response communication mode, the device unit 1 responds to the state confirmation requirement to return status information as parallel data via a data signal line d. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
