Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of BE530540ApublicationCriticalpatent/BE530540A/xx
G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
G05B11/00—Automatic controllers
G05B11/01—Automatic controllers electric
G05B11/012—Automatic controllers electric details of the transmission means
H—ELECTRICITY
H03—ELECTRONIC CIRCUITRY
H03K—PULSE TECHNIQUE
H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04M—TELEPHONIC COMMUNICATION
H04M19/00—Current supply arrangements for telephone systems
H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone
H04M19/04—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone the ringing-current being generated at the substations