Interface unit for blind telephone switchboard operators, 1977
1977
1977
circa 1995
1957
2020
2020-2021
1977
2017
2020
1965-1975
2020-2021
2005-2010
2020
2020
2020
1930
2005-2010
2020-2021
1900-1949
2020-2021
2019
1965-1975
circa 1999 -circa 2005
1965-1975
1965-1975
1957-1962
1957