Lecture 17: Data Communications Interfacing

For example, communicating between two PCs via a telephone line (connected between subscriber's home and local office, then between local offices, and finally between local office and another subscriber's home). The telephone line is an analog system. That means it can not be used for digital transmission. If we try to transmit digital signals over the analog system, our bit rate or bandwidth will be limited to a minimum. On a 4 kHz analog band limited system we can only transmit at a maximum rate of roughly 1 kHz. Because a 1 kHz digital signal needs a bandwidth of 5...

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