Việt hóa từ hình tự do tại <a class="external free" href="https://en.wikipedia.org/wiki/Image:HalfDuplex.JPG">http://en.wikipedia.org/wiki/Image:HalfDuplex.JPG</a>
<a href="https://en.wikipedia.org/wiki/vi:User:Ctmt" class="extiw" title="w:vi:User:Ctmt">Ctmt</a> at <a href="https://en.wikipedia.org/wiki/vi:" class="extiw" title="w:vi:">Vietnamese Wikipedia</a>
7 December 2007 (original upload date)
Transferred from <span class="plainlinks"><a class="external text" href="https://vi.wikipedia.org">vi.wikipedia</a></span> to Commons.