In the case of an intruder, a triggered motion detector can turn on floodlights in the yard and instruct your stereo to queue up the sound of a barking dog. Or say you want to avoid unwelcome guests. By mounting a video camera at the front door, you can view visitors on a TV screen.

第二句话中的say是引导条件状语从句吗？还是接着上面的并列谓语？queue up the sound是什么意思？