VSCII

[2] It should not be confused with the similarly-named unofficial VISCII encoding, which was sometimes used by overseas Vietnamese speakers.

[4] VISCII was also intended to stand for Vietnamese Standard Code for Information Interchange, but is not related to VSCII.

[6] VSCII (TCVN) was used extensively in the north of Vietnam, while VNI was popular in the south.

[4] Unicode and the Windows-1258 code page are now used for virtually all Vietnamese computer data,[citation needed] but legacy files or archived messages may need conversion.

Compared to ASCII, it adds 75 characters: Tone marks on uppercase vowels is accomplished in TCVN3 by switching to an all-capital font.