Computer Communications
Robert H. Chen, Chelsea Chen · 2022
The first electronic communication over distance was the three-state trinary system of Samuel Morse representing letters of the alphabet which combinations thereof could form words and a message. The signals were sent over dedicated transmission lines, but although successful, it could only send messages sequentially one at a time and was so limited in its use as a long-range communications system. Alexander Graham Bell in 1876, constructed a diaphragm in contact with a bag of loose carbon particles and ran a dc current through it, so when a sound vibrates the diaphragm, it will impact the carbon particles changing their density in the bag thereby modulating the current, thus producing an electric current that represents the sound. The term “protocol” is taken from diplomacy where diplomats and high officials are very sensitive to relative rank, so that there are rules for gatherings regarding titles, addressing formalities, priorities such as who goes first, seating, and so on.