
System X circuit board from digital switching subsystem, 1980
1980
1980
(1962); 1982
1981
1981
1982
1980
1982
1981
1981
1982
1981-1982
2000-100 BCE
1982
1980
1980
1982
4000-2001 BCE
1839 (original); circa 1988 (replica)
1981
1903 (original); 1982 (model)
1981
circa 1980
1982
1990-95
circa 1980
1982
1980
1982
1981
1982
1980
1980s
1980
1980
1980
1980
1981-1982
1980
circa 3000 BCE
2000 BCE
2000-400
2000-400
1982
1981
1980
circa 1980
1980
1980
1980
1980