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IT Support & Hardware · Foundational

Serial Port

A legacy RS-232 interface (DB-9) used for console connections and older peripherals.

Definition

Serial ports transmit data one bit at a time and are still used to configure network devices, UPS units, and industrial equipment. Modern laptops use USB-to-serial adapters, which show up as COM ports. Terminal emulators such as PuTTY connect to them.

Example

Connect to a switch console with a USB-to-RJ45 serial cable on COM3 at 9600 baud.

Exam tip

Console access to network devices commonly uses serial settings 9600 8-N-1.

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