I am having a very old Sony Ericcsion w810i mobile phone. I haven’t discarded it yet because its still working well after years of service. I was facing an issue with the phone – it supports only this memory card – Memory Stick PRO Duo. The one I am having is just 512MB which I had got along with the phone. Now I am not finding a new memory card of that format in the market. So coming back to our topic – I love to listen to songs. So I am finding it difficult to include the songs of my collection into the small 512mb card. So I did some research. According to Sony, w810i should support songs in AAC (Advanced Audio Coding) which provides much better compression when compared to mp3. So I converted some songs to aac and put it into my phone. And I have found out that w810i does play aac. So now I am able to include more songs into the memory card due to the less size of acc when compared to mp3.