Citrix CCEA 4.0 Certifications Exam 1Y0-259

The digital and ICT revolutions are twin revolutions. To understand their relationship, let us look at the history EX0-101 of voice telephony. According to Robert W. Lucky, The crux of [Alexander Graham] Bells invention of the telephone in 1875 was the use of analog transmission—the voltage impressed on the line was proportional to the sound pressure at the microphone. [2] The growth of the telephone was relatively slow; it was not until the 1920s that a national telephone network was established in the US. In the EX0-100 late 1940s, an alternative to analog transmission of voice was considered with pulse-code modulation (an encoded signal of pulses). This marked the start of digitization in telecommunications.
However, it was only in 1961 that the first digital carrier system was installed. Digitization meant the widespread replacement of telephone operators with digital switches. In 1971 the first fiber optic 1Y0-259 cables suitable for communications were made, leading to efforts to send communications signals via light waves.