Philips Dect 211 silent mode?

[muvzig]

I've a Philips Dect 211 phone. I'm glad with the overall performance. But there's one thing which makes me feel down about it. I couldn't find a way to bring phone to silent mode. From time to time I want to keep it in silent mode , which the ring volume is off, but I couldn't find a way to do so. Even my old phone had an option for silent mode, I started to doubt there's a way of activating the silent mode. Anyone knows how to make it?