How to get the phone off standby/mute function

Question

I currently own a Doro 615R cordless phone. You do not appear to have any information on this phone. Im hoping you can help me. My phone is currently on standby mode, I need to remove that function. What is happening when you ring my home number, you cannot hear it ring, because obviously a mute function has also been activated. Can you help me and advise me how I go about removing the function. I look forward to hearing from you very soon.Regards Robyn Drake