How are control and data characters distinguished in NVT?
The correct answer and explanation is :
In the Network Virtual Terminal (NVT), control and data characters are distinguished primarily by the ASCII (American Standard Code for Information Interchange) values assigned to them. NVT is a standardized method for communication used in Telnet protocol to represent data across networks.
Correct Answer:
Control characters have ASCII values between 0 and 31, while data characters have ASCII values from 32 to 126.
Explanation:
- Control Characters:
- Control characters in NVT are non-printable characters used to manage the flow of data or perform specific actions, such as signaling the beginning or end of a transmission.
- These characters are encoded using the first 32 ASCII values (0–31).
- They include functions like Carriage Return (CR), Line Feed (LF), Tab, Escape (ESC), and other control signals.
- For example:
- 0x00 (ASCII code 0) represents NUL (Null), signaling no operation.
- 0x0D (ASCII code 13) is CR (Carriage Return), used to return the cursor to the beginning of the line.
- 0x1B (ASCII code 27) is ESC (Escape), which begins escape sequences for special terminal control.
- Data Characters:
- Data characters are printable characters used to convey meaningful information. They are represented by ASCII values from 32 to 126.
- These include uppercase and lowercase letters, digits, punctuation marks, and other symbols.
- For example:
- 0x20 (ASCII code 32) is the Space character, used to separate words.
- 0x41 (ASCII code 65) represents the letter A, and 0x7A (ASCII code 122) represents the letter z.
- Distinction in NVT:
- The NVT distinguishes between data and control characters based on their ASCII codes.
- Data characters are directly interpreted as readable content, while control characters are primarily used for managing the transmission of data, controlling devices, or defining special functions within the protocol.
This distinction allows for effective communication, ensuring that control characters perform their specific functions while data characters are presented as actual content for users or systems.