Arrangement for the transmission of intelligence by the use of the existing telephone network of any suitable central system

摘要

370,045. Exchange systems. NAAMLOOZE VENNOOTSCHAP ELIN NEDERLANDSCHE MAATSCHAPPIJ VOOR ELECTRISCHE INDUSTRIE, Amsterdam. Jan. 2, 1931, No. 237. Convention date, Sept. 11, 1930. [Class 40 (iv).] Signalling means is provided at substations for operation by the insertion of an additional fee or the operation of a counter when a calling subscriber has been extended to a special service station for passing on messages which are recorded phono graphically or by hand, giving information, &c. The signalling means may be a gong &c. acting in conjunction with a special microphone a short-circuit around which is removed when a signal is to be given, or a buzzer. The microphone and buzzer are shunted by chokes to prevent accidental release of the switching train. The Figure shows a switch for connecting up the buzzer, the spring V in conjunction with the studs on the disc R causing a momentary change over of the springs FP1 however long the push T1 is held. In this case an electrically operated counter in series with the buzzer is operated when T1 is pressed. The bell and buzzer signals may be replaced by current impulses in the line. The pushbutton may be replaced by a removable key of special shape.