| 摘要 |
PURPOSE:To decrease number of interfaces to a line terminator, by using a part of lines contained in communication controllers for the connecting control for communication controller and the line terminator. CONSTITUTION:When a communication controller ''0'' is selected, a CPU outputs ''0'' to a SD line if an AD and a WSB are all at ''1''. One of inputs of a coincidence circuit 3 is always set to ''0'', and when an FF2 outputs ''0'', the coincidence is detected and ''1'' is outputted. Since this output is inputted to a distribution circuit 8 via gate circuits 4, 5 the transmission data multiplexed from the CPU is distributed to each line via the communication controller ''0'' side. On the other hand, since the ''1'' detecting circuit 9 detects ''1'' of the AD and WSB line and outputs ''1'', the output of a multiplexer 13 passes through a gate circuit 14. Thus, the reception data from each line is transmitted to the CPU via the communication controller ''0'' side. In case of using the communication controller ''1'', the process is made similarly. |
