I was just reading a Q&A here about Chinese words for DVD and the discussion also included other acronyms from English.
It struck me that nobody wrote the pinyin for any of the terms which made me think it means the tones must be obvious so the logical conclusion was that they are all neutral tone.
But is this assumption correct and is it always the case? Also are such words ever affected by tone sandhi?
It seems this question is not clear to all readers. I'm specifically asking about tones, not about writing, though Pinyin is a good way to illustrate the tones. I couldn't find the pinyin for DVD but if the Wiktionary entry for CD is correct then it in fact uses the fourth, falling, tone for each syllable:
So maybe I should change the question to ask if they always use falling tone for all syllables?
I'm interested in both viewpoints: prescriptive (what, if anything, Standard Chinese has to say about borrowed acronyms) and descriptive (how various Chinese speakers pronounce them in their natural speech, especially those who do not know English).