Telephony, Telephones Ericsson telephone handset, c 1920s

Telephony, Telephones Ericsson telephone handset, c 1920s. This sectioned handset shows both the earpiece and mouthpiece of a 1920s Ericsson telephone. Within the earpiece, two wire coils combine to vary the field of the permanent magnet. An iron diaphragm lies beneath the magnet, and allows the soundwaves to be heard. Inside the mouthpiece, a perforated screen protects the diaphragm while still allowing soundwaves to pass through. The Ericsson company was founded by Lars Magnus Ericsson (1846-1926), a Swedish telegraph instrument repairer. After Bell invented the first telephone in 1876, people brought their phones to be repaired and his firm began producing their own phones. By the early 20th century, the business had expanded into Europe and the United States. Today, Ericsson has facilities in over 140 countries worldwide. ©SSPL/Science Museum