A:AnswerProbably just an AUX audio cord. There is no optical input on this monitor, but there is a headphone output & audio input via AUX cable that you can run from your preamp
A:AnswerWe are sorry to hear this- please contact Acer support for assistance with your monitor as they will be happy to help you get this resolved. Contact information is posted here for your convenience: https://www.acer.com/ac/en/US/content/service-contact
A:AnswerIt is a little difficult at first but there are two pegs on the stand that have to be depressed and hen the height adjusts and you can press the pegs again and it “locks” in place.