Aquapac
Aquapac is a registered trademark and brand name of a UK-based manufacturing company, Aquapac International Limited, specializing in waterproof cases and bags. The privately owned company was formed in 1983 and holds patents worldwide on systems for sealing bags and cases. The range commenced with a waterproof case for the original Sony Walkman known as the ‘Aquaman’, followed by cases for handheld VHF radios. Following Motorola’s invention of the first cellphone Aquapac launched the world’s first waterproof cellphone case. Nokia was an important customer for these cases during the 1990s, as were cellphone operators such as Deutsche Telekom and NTT DoCoMo. Aquapac went on to launch waterproof cases for other handheld electronics such as cameras and eReaders. The company operates out of factories in London, England.
Telephone
In 1876, shortly after the telephone was invented, Hungarian engineer Tivadar Puskás invented the telephone switch, which allowed for the formation of telephone exchanges, and eventually networks.Early telephones were technically diverse. Some used a water microphone, some had a metal diaphragm that induced current in an electromagnet wound around a permanent magnet, and some were dynamic – their diaphragm vibrated a coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic variants survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power was crucial. Most, however, used the Edison/Berliner carbon transmitter, which was much louder than the other kinds, even though it required an induction coil which was an impedance matching transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by which time the network was more important than the instrument.