| 摘要 |
PURPOSE:To obtain a system where a switch matrix is constituted with two make contacts, by combining a gate control rectifying element with current holding switches. CONSTITUTION:An incoming is displayed on a B board by hook-up of a telephone set TEL; and when the server responds to it, he can speak with the telephone set TEL. At this time, an SOO lead of extension designation becomes H- level. Next, when the server performs the trunk designating operation for the purpose of originating a signal to a trunk line, a trunk designating lead becomes H-level. Consequently, the output of an integrated circuit IC becomes H-level, and a gate control rectifying element SR is turned on, and therefore, a lead relay OO having two make contacts constituting a cross point is operated and held because a current is flowed through the course of a battery +24V a resistance R the winding of the relay OO the element SR a transistor an earth E. By this sequence, the telephone set TEL is connected to the trunk line through the OO cross point. |
