ISDN
ISDN brings some relief to the speed limitations of analog modems by offering speed up to 1.5 Mbps for Primary Rate Interface (PRI), or a more commonly used rate that is offered by most phone companies, the Basic Rate Interface (BRI). BRI offers speed up to 128 kbps, significantly faster than traditional analog speed.
So what makes ISDN able to achieve such high speeds that analog modems can’t? To fully understand the difference between analog modems and ISDN, we need to take a look at how voice is encoded into a digital signal level 0 (DS-0) channel.
To convert an analog voice into digital signal, the required sampling rate is 8000 samples per second; therefore, 8 bits are needed to represent each sample. Therefore, the bandwidth needed ...
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