Japan's Docomo Unveils 3G Phones with 3D Sound  TOKYO (Reuters) - Japan's largest mobile operator, NTT  DoCoMo Inc. &lt;A HREF="http://www.reuters.co.uk/financeQuoteLookup.jhtml?ticker=9437.T qtype=sym infotype=info qcat=news"&gt;9437.T&lt;/A&gt;, unveiled on Wednesday a new line of  advanced mobile phones with stereo-quality surround sound,  high-resolution digital cameras, and a special chip that allows  owners to use their phones as a debit card.