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.)
Filing date
Publication date
Application filed by Telefonica Nacional Espana CofiledCriticalTelefonica Nacional Espana Co
Priority to PT8725888ApriorityCriticalpatent/PT87258B/pt
Publication of PT87258ApublicationCriticalpatent/PT87258A/pt
Publication of PT87258BpublicationCriticalpatent/PT87258B/pt
Circuit arrangement for the operation of call handling or information positions in centrally controlled telephone exchanges, especially multiple operator's position exchanges