What amount of data can be transmitted digitally?

v4+ maximum

Explanation:

8.7 Digital Transmission Protocols

Digital transmission has very significant advantages compared with analog transmission because the possibility of signal corruption during transmission is greatly reduced. Many different protocols exist for digital signal transmission. However, the protocol that is normally used for the transmission of data from a measurement sensor or circuit is asynchronous serial transmission, with other forms of transmission being reserved for use in instrumentation and computer networks. Asynchronous transmission involves converting an analog voltage signal into a binary equivalent, using an analog-to-digital converter. This is then transmitted as a sequence of voltage pulses of equal width that represent binary “1” and “0” digits. Commonly, a voltage level of either +5 V or +6 V is used to represent binary “1” and 0 V represents binary “0.” Thus, the transmitted signal takes the form of a sequence of 6 V pulses separated by 0 V pulses. This is often known by the name of pulse code modulation. Such transmission in digital format provides very high immunity to noise because noise is typically much smaller than the amplitude of a pulse representing binary 1. At the receiving end of a transmitted signal, any pulse level between 0 and 3 V can be interpreted as a binary “0” and anything greater than 3 V can be interpreted as a binary “1.” A further advantage of digital transmission is that other information, such as the status of industrial equipment, can be conveyed as well as parameter values. However, consideration must be given to the potential problems of aliasing and quantization, as discussed in Chapter 6, and the sampling frequency must therefore be chosen carefully.