The Lisbon Telephone Exchange inaugurated its inter-urban switchboard with the establishment of an international connection between Lisbon and Madrid, allowing access to the international phone network via Spain. The connection was established on 17th May 1928 and was the result of 16 years of negotiations between the Portuguese and Spanish governments. Contacts were initiated when the Department head, Benjamim Pinto de Carvalho, visited Spain to see how the Madrid-Paris phone line had been set up. The idea of installing a line to connect the two countries interested Spain, but as the necessary resources were unavailable, the Spanish government was forced to call off negotiations. The project was restarted by Humberto da Cunha Serrão in 1917, but the terms of negotiation between Portugal and Spain were only put in place in 1924 when General Primo Rivera awarded the general telephone service concession to Companhia Telefónica de Espanha. Humberto Júlio da Cunha Serrão was born in Coimbra in 1885. In 1908, he finished a secondary course on the telegraph and was transferred to the Electrical Installation and Telephone Line Monitoring Department (DFIELT). When Portugal entered the First World War (1916), Humberto Serrão joined the Portuguese Expeditionary Force, entering the Field Postal Service. After demobbing in June 1919, he was appointed head of the 1st Section of the Electro-technical Services Dept. (DSE). As the main driver behind the expansion of the Baudot system in the telegraph network, he oversaw the remodelling and reorganisation of the General Workshops at the Tapada das Necessidades from 1926-1928. He retired in the 1950s, prior to which he held the position of Director of Industrial Services.