computer science

VSCII

VSCII is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand VSCII rather than just read about it. In short: VSCII (Vietnamese Standard Code for Information Interchange), also known as TCVN 5712, ISO-IR-180, .VN, ABC or simply the TCVN encodings, is a set of three closely related Vietnamese national standard character encodings for using the Vietnamese language with computers, developed by the TCVN Technical Committee on Information Technology (TCVN/TC1) and first adopted in 1993 (as TCVN 5712:1993). It should not be confu…

Key takeaways

VSCII belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect VSCII to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of VSCII from memory before moving on to harder problems.

Reference excerpt

VSCII (Vietnamese Standard Code for Information Interchange), also known as TCVN 5712, ISO-IR-180, .VN, ABC or simply the TCVN encodings, is a set of three closely related Vietnamese national standard character encodings for using the Vietnamese language with computers, developed by the TCVN Technical Committee on Information Technology (TCVN/TC1) and first adopted in 1993 (as TCVN 5712:1993). It should not be confused with the similarly-named unofficial VISCII encoding, which was sometimes used by overseas Vietnamese speakers. VISCII was also intended to stand for Vietnamese Standard Code for Information Interchange, but is not related to VSCII. VSCII (TCVN) was used extensively in the north of Vietnam, while VNI was popular in the south. Unicode and the Windows-1258 code page are now used for virtually all Vietnamese computer data, but legacy files or archived messages may need conversion.

Encodings All three forms of VSCII keep the 95 printable characters of ASCII unmodified. VSCII-3, also known as TCVN 5712-3, VN3 or simply TCVN3, includes the fewest assignments. It is an extended ASCII, because it keeps all 128 codes of ASCII unmodified. It does not reassign any of the C0 and C1 control codes. Compared to ASCII, it adds 75 characters:

67 lowercase characters, allowing full lowercase support. 7 uppercase characters, allowing uppercase support for the 29 base letters without tone marks. The non-breaking space. Tone marks on uppercase vowels is accomplished in TCVN3 by switching to an all-capital font. VSCII-2, also known as TCVN 5712-2 and VN2, is a superset of VSCII-3. It is an extended ASCII, because it keeps all 128 codes of ASCII unmodified. It does not reassign any of the C0 and C1 control codes, making it conformant with ISO 2022 as a 96-set. Compared to VSCII-3, it adds (for a total of 96 non-ASCII characters):

16 more uppercase characters with pre-composed tone marks (for a total of 23 non-ASCII uppercase characters) 5 combining diacritics for tone marks, allowing other combinations of uppercase letters and tone marks to be represented. Combining marks follow the base letter as in VNI (rather than preceding them as in ANSEL). VSCII-1, also known as TCVN 5712-1 and VN1, is an extension of VSCII-2, and is a modified ASCII, since it replaces 12 of the 33 control characters with precomposed characters. Compared to VSCII-2, it (for a total of 140 non-ASCII characters):

Adds 44 more pre-composed uppercase letters, bringing them to the same count as the lowercase Does this by replacing 12 ASCII control characters and allocating 32 graphical characters to the C1 control area, breaking ISO 2022 compatibility Conversion from VSCII-3 to VSCII-2 or VSCII-1 and conversion from VSCII-2 to VSCII-1 are not necessary, but can result in smaller files. Conversion from VSCII-1 to VSCII-2 or VSCII-3 and conversion from VSCII-2 to VSCII-3 require expansion of some pre-composed characters.

Character set

References

External links tables with Unicode points and names

Worked examples

Example 1 — a first encounter with VSCII

Start with the simplest possible case. Write down what VSCII claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to VSCII before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about VSCII ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of VSCII

In research: VSCII appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses VSCII in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: VSCII is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1993 establishments in Vietnam, Character sets, Computer-related introductions in 1993, so understanding it makes those chapters shorter.
In everyday life: Look for VSCII outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study VSCII in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what VSCII means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain VSCII out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is VSCII in simple terms?

Why does VSCII matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study VSCII?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on VSCII.