At the carrier switching office, the voice is separated from the data and converted back to regular circuit-switched voice.

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However, VOIP differs from the usual phone services in that it sends calls as digital packets of information over data networks rather than relying on a dedicated circuit-switched network.

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Pearse and others dream of unifying the mess, with a box that blends both optics and electronics, fusing the circuit-switched world of phone calls and packet-switched world of Internet data.

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