VAC simulates an audio adapter (card) and provides a set of virtual audio devices named Virtual Cables. With VAC, you can transmit sounds from any application to any other. Windows audio application can produce (play back) and/or record sounds (audio signals) too.
You definitely know that traditional hardware audio devices (CD/LP player, FM receiver, equalizer, amplifier etc.) may be connected together by electric (analog or digital) cables.
VAC routes audio signals (streams) between such connected applications, keeping as low latency as possible.
Virtual Audio Cable software (VAC), allows you to connect audio applications to each other.