| 摘要 |
PURPOSE:To prevent ineffective holding of line, by transmitting a cutoff signal to all lines through the instruction of a common control section in case of failures. CONSTITUTION:When transmission of transmission data SD and line numbers A0-A7 are disable with device failures, a cutoff instruction signal AL is given from a common controller, a counter CTR is started, gates G0-G7, GS are closed and gates C0'-G7', GS' are opened. As a result, with the count of a counter CTR, line numbers A0'-A7' and A polarity data signal are sequentially transmitted to a time division line concentration circuit DST via gates G0'-G7', GS'. The circuit DST transmits the A polarity data signal to each line DL sequentially. Thus, after a given time, they are regarded as cutoff signals, and each line DL is released. Thus, the ineffective holding of lines can be prevented. |
