ISDN stands for Integrated Services Digital Network.
In sound recording (without getting into all the technical stuff) it's a way of connecting two studios together with very little loss of quality. So I could sit in my studio in London and connect with someone in the States who also has an ISDN line. It looks just like a phone line with a fancy box on the end. In the UK, not surprisingly BT is the main supplier.
However, it isn't quite that simple. The sounds going into a microphones in both studios have to be digitized so they can be sent on the ISDN line. This means both studios need a codec
What's a CODEC?
Short for coder-decoder it turns the analogue sound into digital and vice versa. My codec is a Pronto 2 and looks pretty much like an amplifier. I speak into a microphone, which is connected to a small audio mixer to control sound levels. This is connected to the codec, which is connected to the ISDN line. At the other end, the other studio receives the signal into their codec, which is then plugged through to their recording equipment, and they monitor it through headphones or speakers.
There are various other codecs.
Prima springs to mind, and is very popular. A software application called AudioTX has also been developed which means your PC effectively becomes the codec.
So what's the point of ISDN?
Radio stations love it. Instead of having to use the same voices living locally, or those prepared to travel large distances, they can now choose anyone in the world with an ISDN line and the rest of the kit. Voice artists love it because they can stay at home (wherever that is, maybe miles from civilisation) and not even get dressed to go to work!
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