1929
1931
1930: 1930 Bell Ten Line Intercom
1930: Kellogg 925
1930: Kellogg 9917
1930: Pope Pius XI's golden phone
1930: Stromberg-Carlson 1211
1930: Stromberg-Carlson 1212
1930: WE 201 Spacesaver
1930: WE 202
1930: WE 202 Imperial
1930: WE 653 Hotel Phone
1930: WE E5 208 Key Set
1930: Anti-sidetone circuit developed
1930: AT&T Annual Report, 1930
1930: Submarine cable ad
1930: Phone Pioneers Talk Telephone
1930: Ericsson 1930 catalog
1930: Telephone Buildings Of The Bell System