"Dazheng" and "Taisho" are interchangeable terms/words from what I can tell. I also believe the term "wistek", in and of itself, is a generic term to mean "wise tech" a/k/a smart technology.
Dazheng/DC/Wistek/related sub-companies are rooted in Taiwan and are essentially a big part of the growth plans of the region. Just quickly browsing Hanwang/Hanvon, I don't see them as being part of the same group. However, there might be a supplier relationship between them.
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