Chinese switchboard operator at work at a telephone exhange in Chinatown, San Francisco, USA. The switchboard was set up in 1894 to serve subscribers. The operators knew each subscriber by name as it was felt to be rude to refer to people by numbers. The operators also knew each subscriber's address and occupation so that they could distinguish between two people with the same name. The operators spoke five Chinese dialects and English. The offices of the telephone exchange were destroyed by an earthquake in 1906, but were rebuilt and remained in operation until 1949, when technology changed from a switchboard operator system to rotary-dial telephones.