Setup as above, the caller receives all Broadcast Audio, including hosts, bumper music, etc. The caller, however, does not receive his or her own audio signal. In effect, the caller receives a Mix-Minus feed of the Broadcast Audio.
In order to take a call, the host using Computer 1 simply accepts the Skype call, and uses the M-Audio Delta Control Panel to increase the level of H/W In 1/2, which is the caller audio. This injects the caller audio into Computer 1's monitor stream, which thereby injects the caller audio into the Broadcast Audio.