Mediation office
Switching offices were necessary in telecommunications before the self-dialing device was invented around 1889 .
Central offices ( telephone exchanges ) were from about 1878 in North America to the switching of telephone communications established between the residents of one and the same place.
From a central office, wires were pulled into the participants' apartments and connected to the telephone sets. At the central office, the so-called switching office, technical facilities were created with which any connections between the subscriber lines could be established.
Connected participants both had the opportunity to converse directly with each other participant by telephone, as well as the possibility of sending messages to the switching office for further transport. Like all telegraphic equipment in the United States, these urban telephone systems were manufactured and operated by private companies.
Similar institutions soon followed in London and Paris ; In 1880 the German Reichs-Telegraphenverwaltung followed, which opened the operation of telephone systems in 1881 in Berlin and soon after in Mulhouse ( Alsace ), Frankfurt am Main and Hamburg ; In January 1885, general telephone systems were already in operation or being implemented in 58 cities in the Reichspostgebiet. 7,311 people attended the facilities; the total length of the city telephone lines was 16,291 kilometers.
literature
- Grawinkel: Textbook of Telephone and Microphone (2nd edition). Berlin 1884
- Wietlisbach: Telephony technology . Vienna 1886
- Meili: Telephone law . Leipzig 1885