Portable Mining Magneto Telephone Portable Mining Magneto Telephone. A Portable Mining Magneto Telephone. Made by Ericsson. Type N-1846. Made from Tin and Bakelite. Size 10″ x 6″ x 5″ inches. This telephone unit has its winding key integrated into the body. Dated 1948. 2018-11-17 grahamgeorge