COM 1 shares an IRQ with which other COM port?

COM 1 shares an IRQ with which other COM port?

• A. COM 2
• B. COM 3
• C. COM 4
• D. COM 5

Answer: (B)

The correct choice is that COM 1 shares an IRQ (Interrupt Request Line) with COM 3. In traditional PC architecture, certain COM ports are designed to share IRQs. Specifically, COM 1 typically uses IRQ 4, while COM 3, being the second serial port in the group, is configured to share this IRQ. Understanding this is important because IRQs are vital for device communication with the CPU, and sharing them helps allocate system resources effectively. The connection of COM 1 and COM 3 allows both to communicate with the CPU, but care must be taken to avoid conflicts that could arise from both ports trying to use the same resources simultaneously. By contrast, other COM ports like COM 2, COM 4, and COM 5 typically allocated different IRQs to ensure they can function independently without interference from overloading a single line. Thus, the unique pairing of COM 1 and COM 3 regarding IRQ sharing is an essential concept in configuring and troubleshooting serial communication in computing.

The correct choice is that COM 1 shares an IRQ (Interrupt Request Line) with COM 3. In traditional PC architecture, certain COM ports are designed to share IRQs. Specifically, COM 1 typically uses IRQ 4, while COM 3, being the second serial port in the group, is configured to share this IRQ.

Understanding this is important because IRQs are vital for device communication with the CPU, and sharing them helps allocate system resources effectively. The connection of COM 1 and COM 3 allows both to communicate with the CPU, but care must be taken to avoid conflicts that could arise from both ports trying to use the same resources simultaneously.

By contrast, other COM ports like COM 2, COM 4, and COM 5 typically allocated different IRQs to ensure they can function independently without interference from overloading a single line. Thus, the unique pairing of COM 1 and COM 3 regarding IRQ sharing is an essential concept in configuring and troubleshooting serial communication in computing.