In computer hardware interfaces, which standard specifically governs parallel communications between a computer and external devices such as printers?

Introduction / Context:
This question tests basic knowledge of computer hardware communication standards. In older but still exam relevant computer systems, separate standards were defined for serial communication and for parallel communication between a computer and external devices such as printers. Knowing which standard applies to parallel ports helps you distinguish it from cabling categories, serial interfaces and newer technologies like USB. This is a common fact based question in computer awareness sections.

Given Data / Assumptions:

• The focus is on parallel communications between a computer and external devices.
• The question asks which standard governs or defines this kind of communication.
• Options mention CAT 5, IEEE 1284, RS-232, USB and None of the above.
• We assume typical desktop computers with traditional printer ports as discussed in many textbooks.

Concept / Approach:
Parallel communication sends multiple bits of data simultaneously over several wires. Older printers and some external devices connected to a parallel port on the computer, often called a Centronics port or printer port. The formal standard that governs parallel port communication between a computer and a printer is IEEE 1284. It defines electrical characteristics, signal lines and negotiation modes for bidirectional parallel communication. RS-232, on the other hand, is a standard for serial communication that sends bits one after another over a single data line. CAT 5 describes twisted pair cabling, not a port standard. USB is a newer serial based interface. Therefore, IEEE 1284 is the correct standard for parallel communications in this context.

Step-by-Step Solution:

Verification / Alternative check:
Hardware reference material usually lists IEEE 1284 as the standard that upgraded older Centronics interfaces and defined enhanced parallel port modes such as EPP and ECP. In the same tables, RS-232 is listed as a serial interface standard, and CAT 5 appears under cabling categories used for Ethernet and networking. USB is described as a universal serial bus with its own specifications, not as a parallel communication standard. This separation in the documentation confirms that IEEE 1284 is the correct answer when the question mentions parallel communications between computers and printers.

Why Other Options Are Wrong:

• CAT 5 (Category 5 cabling): Specifies network cable characteristics and is mostly used for Ethernet, not directly for parallel ports.
• RS-232: A standard for serial communication, so it does not govern parallel interfaces.
• USB: A universal serial bus standard and therefore not a parallel communication standard.
• None of the above: Incorrect because IEEE 1284 clearly matches the requirement.

Common Pitfalls:
Candidates sometimes confuse RS-232 with general communication and forget that it is strictly serial. Others may see CAT 5 and think of connections in general without noticing that it is just a cabling category. To avoid such mistakes, link the key words in memory: IEEE 1284 for parallel printer port, RS-232 for serial port and USB for modern serial bus. When you see a direct question about the standard for parallel communications, IEEE 1284 should be your automatic choice.

Final Answer:
The standard that governs parallel communications between a computer and devices such as printers is IEEE 1284.