A consortium of computer hardware and software companies including Compaq, DEC and Microsoft. A version of the AC logic chips which allows easy connection to TTL logic chips. It's the job of the ADC to convert the one sort of information into the other. This voltage can then be amplified and fed to the ADC unit. This code can now be used by the Computer.
Sound cards are circuit boards which greatly improve the PC's sound output quality.
They use sound stored in digital form. The sound amplitude is frequently sampled by an ADC circuit, each sample being represented by, say, a 12- bit code. PCM works out the code for each sample 'from scratch' each time. A Wide are networking system which gives an incoming data stream of up to 9Mbps. It will run over traditional twisted pair telephone cable alongside existing phone services.