IT FundamentalsA+

Peripheral Devices for CompTIA A+ 220-1101

Peripheral devices extend the capabilities of a computer through input, output, and storage expansion. CompTIA A+ 220-1101 tests identification, connection, and configuration of common peripherals — keyboards, mice, scanners, webcams, headsets, and specialty devices. Peripheral support is one of the most common IT help-desk tasks.

6 min

1 sections · 7 exam key points

1 practice questions

Input and Output Devices

Keyboards and mice: wired (USB-A) — plug and play, no batteries, reliable. Wireless — 2.4 GHz dongle (USB receiver) or Bluetooth. Dongle-based wireless is more reliable and has lower latency than Bluetooth; Bluetooth saves the USB port. Ergonomic keyboards and mice reduce RSI (repetitive strain injury). Keyboard not working: try different USB port, test on another PC, check for spill damage, verify USB drivers, try PS/2 adapter if available.

Scanners: flatbed scanner (places document on glass plate) — for photos and documents. ADF (Automatic Document Feeder) — feeds multiple pages automatically, found on multifunction printers/scanners. Sheet-fed scanner — pulls individual pages through (no flatbed). Drivers: TWAIN driver standard allows scanning software to communicate with the scanner. WIA (Windows Image Acquisition) — Microsoft standard, built into Windows, allows scanning without third-party software.

Webcams: built-in (laptops, most monitors) or external USB webcam. Resolution: 720p, 1080p, 4K. Frame rate: 30fps or 60fps. Issues: device not recognized (check Device Manager, update driver, try different USB port), video is blurry (focus adjustment, clean lens), no audio (check audio settings — webcam may have built-in microphone, verify input device selected in application).

Speakers and headsets: 3.5mm audio jack — analog audio (green = output, pink = microphone, blue = line-in on desktop audio jacks). USB audio: digital audio converted in the headset — bypasses system audio hardware. Bluetooth audio: A2DP profile for stereo audio. Common issue: wrong audio output device selected — check Windows sound settings (right-click speaker icon → Open Sound settings → Output device). Hearing hearing only from one ear: check audio balance settings.

Signature pads: capture handwritten signatures digitally — used in retail, banking, medical. Connect via USB, require specific driver and application software. Biometric readers: fingerprint readers for Windows Hello — most modern laptops have built-in fingerprint sensors; external USB fingerprint readers available for desktops.

Key exam facts — A+

2.4 GHz dongle wireless: lower latency than Bluetooth, uses USB port for receiver
Flatbed scanner: glass plate for photos/documents; ADF: automatic multiple-page feeding
TWAIN: scanner driver standard; WIA: Windows Image Acquisition (built-in Windows)
3.5mm audio: green=output, pink=mic, blue=line-in; USB audio: digital signal in device
Webcam not recognized: check Device Manager, update driver, try different USB port
Audio from one ear: check balance setting in Windows sound properties
KVM switch: keyboard/video/mouse switch for controlling multiple PCs from one set of peripherals

Common exam traps

All USB devices work immediately without drivers

Most simple HID (Human Interface Device) USB peripherals (keyboards, mice, basic webcams) use built-in Windows class drivers and work without additional installation. However, specialty devices (drawing tablets, advanced webcams, scanners, signature pads) require manufacturer drivers for full functionality. Always install manufacturer drivers for peripherals that don't work with the Windows generic driver

Practice questions — Peripheral Devices

These questions are representative of what you will see on A+ exams. The correct answer and explanation are shown immediately below each question.

Q1.A user plugs in a USB scanner and Windows recognizes the device, but the scanning software returns an error when trying to scan. What should the technician do first?

A.Replace the scanner

B.Install the manufacturer's TWAIN or WIA driver from the manufacturer's website

C.Reinstall Windows

D.Replace the USB cable

Explanation: Windows recognizing the device (basic USB detection) is separate from the scanner functioning correctly for scanning operations. Scanning requires either the manufacturer's TWAIN driver (for use with specific scanning software) or a WIA driver. Windows may have loaded a generic driver that provides basic recognition but not full scanning support. Download and install the correct driver from the manufacturer's website, then restart the scanning application.

Frequently asked questions — Peripheral Devices

What is a KVM switch and when is it used?

A KVM (Keyboard, Video, Mouse) switch allows a single set of keyboard, monitor, and mouse to control multiple computers by switching between them with a button press or keyboard shortcut. Used when a technician or administrator manages multiple physical servers or workstations at a console, or when a user has both a work and personal computer on the same desk and wants to avoid having two keyboard/mouse/monitor sets. KVM switches come in 2-port (two computers), 4-port, 8-port, and larger configurations.

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