| 摘要 |
PURPOSE:To quickly select vacant lines, by providing a means storing the usage state of crossing points of vertical or horizontal paths in a crossbar switch for a control circuit of a telephone exchanger. CONSTITUTION:In a circuit controlling a crossbar switch, when a subscriber picks up a handset, since a microcomputer (not shown) of a marker section is connected to a vacant originating register, a terminals corresponding to the vertical path where a contact at cross points of the vertical and horizontal paths of the primary switch of the crossbar switch is opened and corresponding terminal 3 is made to ''0'' V, and a photocoupler 13 corresponding to the contact 13 is operative and a corresponding relay drive section 23 is activated. Thus, a busy detection contact 33 is closed, a terminal 53 is made to ''0'' V via a chattering preventing circuit, the display in use is made to the microcomputer, a driving contact 63 is closed with the driving section 23, a coil 73 of the crossbar switch is driven, the 3rd vertical path is selected and connected with a horizontal path from the subscriber. |
