CompTIA A+ Practice Test (220-1201)

VoIP audio and video streams typically ride on the Real-time Transport Protocol (RTP), which in turn uses UDP. UDP is connectionless and does not wait for acknowledgments or retransmit lost packets, so it introduces less overhead, latency, and jitter than TCP. TCP's handshake, sequencing, and retransmission mechanisms improve reliability but add delay, making it unsuitable for real-time voice traffic in most cases. HTTP and ICMP are not used to carry VoIP media, and while TCP can be used, it normally degrades call quality compared with UDP.

Buzzing or crackling that begins immediately after a speaker replacement almost always points to a bad physical connection: the small speaker cable or the driver itself is not fully seated, so the signal intermittently opens or shorts and the cone can vibrate against the chassis. Reseating the cable and mounting the speaker correctly normally restores clear audio. A leaky speaker enclosure can affect frequency response but rarely creates an electrical buzz, electromagnetic interference is typically heard as faint hiss or clicks, and an impedance mismatch can indeed cause distortion-but technicians usually install the manufacturer-specified part, so a loose connection is by far the more likely cause.

Metered utilization is the correct answer because it refers to the characteristic of cloud computing where customers only pay for the resources they use, rather than a flat fee. This means that costs directly reflect actual usage. In comparison, high availability refers to the uptime and reliability of services, rapid elasticity to the ability to scale resources quickly in response to demand, and shared resources to the pooling of resources to serve multiple consumers, but none of these directly correlate cost with usage like metered utilization does.

The Fn key (short for "function") is a modifier key that lets laptop makers assign alternate commands-volume, brightness, external-display toggle, and more-to keys that would otherwise have a single purpose. By eliminating the need for dedicated media or hardware-control keys, the Fn key enables a more compact keyboard layout and therefore thinner, lighter laptops.

Keystone correction is specifically related to adjusting the image output when a projector is not positioned perpendicular to the screen, which can lead to distortion primarily at the sides but could potentially affect focus distribution if severe. Despite feeling intuitive, cleaning the lens or adjusting resolution may not address a central blur when the edges are clear; and updating the software deals with processing but it's uncommon for this to specifically affect focal sharpness. Thus, recalibrating the lens properties such as focus would be a logical step before assuming other hardware or software failures.

Lower-frequency signals travel farther and penetrate solid obstacles more effectively than higher-frequency signals because they experience less free-space path loss and better diffraction. The 2.4 GHz band therefore offers the best range and wall penetration, making it the logical choice when coverage is the primary goal. The 5 GHz and 6 GHz bands provide higher data rates but their shorter wavelengths attenuate more quickly and are blocked more easily by shelves and concrete. A 60 GHz millimeter-wave band would have even poorer range indoors and is not part of standard Wi-Fi deployments for warehouse coverage.

The public cloud is a model where services are offered over the internet and are available to anyone willing to pay for them. It is managed by third-party providers and offers scalability and flexibility for users.

The cloud computing characteristic rapid elasticity provides the ability to expand or contract resources as the need or lack thereof arises. The biggest advance of this is being able to add resources faster and cheaper than adding additional hardware.

Dynamic Host Configuration Protocol (DHCP) is used to assign IP addresses to devices on a network automatically. When a device connects to a network, it sends a request to the DHCP server, which then leases an IP address to the device. This protocol simplifies network management by eliminating the need for manual IP configuration. SNMP is used for managing and monitoring network devices but is not responsible for IP assignment. IMAP is used to retrieve emails from a server and also doesn't handle IP addressing. RDP allows remote connection to another computer but does not relate to assigning IP addresses.

When a device is assigned an address that starts with 169.254, it indicates that it has self-assigned an Automatic Private IP Addressing (APIPA) address. This is a fallback mechanism used when a workstation configured to obtain an address automatically is unable to reach a DHCP server to obtain one. This typically points to issues with the DHCP server itself being unreachable or malfunctioning. It is not due to manual static address configuration, incorrect subnet settings, or interference from a rogue DHCP server, as those scenarios would lead to different outcomes such as deliberate network assignment, connectivity issues related to incorrect network segmentation, or invalid network configurations respectively.

A public cloud model provides infrastructure and services on-demand over the internet, using infrastructure shared by all customers of the cloud provider. Examples include Amazon Web Services (AWS), Google Cloud Platform (GCP), and Microsoft Azure. By using a public cloud model, your client can migrate out of their on-premise data center and use the flexibility and ad-hoc subscription model of a public cloud. A hybrid cloud is incorrect as it involves retaining some on-premise infrastructure. A private cloud is dedicated to a single organization and is less aligned with the client's desire for a flexible, ad-hoc model. A community cloud is a collaborative model for organizations with shared concerns and is not suitable for a single organization's general needs.

The trapezoidal, 7 mm-wide, five-pin connector with beveled top corners matches the USB mini-B style that was common on mobile devices prior to the adoption of micro-USB and USB-C. Micro-USB connectors are smaller (about 6.8 mm × 1.8 mm) with a distinct stepped shape, USB-C is a thin symmetrical oval, and Lightning is proprietary to Apple devices-none of which would fit a legacy mini-B receptacle.

The fuser assembly uses heat and pressure to melt and fuse toner onto the paper. When a fuser assembly is failing, it may not properly bond all the toner, or the cleaning mechanism for its roller might fail. This can cause leftover toner from a previous image to stick to the fuser and be transferred onto the next page, creating a faint, ghosted image. The other components listed cause different issues: faulty separation pads or pickup assemblies lead to paper-feeding problems, while a defective corona wire typically causes faded or blank printing.

IMAP (Internet Message Access Protocol) is a standard email protocol that stores email messages on a mail server and allows the user to view and manipulate them as if they were stored locally on their device's mail client. IMAP operates over port 143, where it maintains a continuous connection to the mail server, allowing users to organize, delete, or mark their email without having to download it first. This continuous connection enables real-time updates of the email status across multiple devices, making it ideal for users who need to access their mail from various locations and devices.

Display burn-in, also known as screen burn, is the result of displaying the same image or scene for an extended period, leading to some pixels aging differently than others and causing a permanent 'ghost' image. This symptom differs from temporary screen artifacts or image retention, which can usually be corrected by changing the display content or turning the screen off for a while.

In any case wherein a system can't find the bootable device, especially when dealing with a mirrored set of drives purposed for redundancy, checking the physical connections is a fast and straightforward initial diagnosis to see if the error is related to simple issues such as loose cables. This step may quickly solve the problem since if the system can't properly communicate with the storage devices, it will not be able to boot or recognize either of them.

Syslog servers normally listen on UDP port 514 to accept log messages from network devices and operating systems. IT professionals must know common port numbers to configure firewalls, set permissions, and troubleshoot connectivity. Port 389 is reserved for LDAP directory services, port 162 is used for SNMP trap notifications, and port 25 is the default SMTP port for email transfer-none of these handle syslog traffic.

These symptoms describe a phone that is in airplane mode. The best option available would be to disable airplane mode. On most smart phones you could also re-enable WiFi and keep Airplane mode.

Tap-to-pay mobile payments require the tablet's near-field communication (NFC) radio and antenna to be present and enabled so the device can exchange payment data with the terminal at a range of a few centimeters. If the terminal is working but the tablet cannot connect, the NFC module (antenna/chip) is the most likely point of failure or misconfiguration. A webcam, Bluetooth radio, or GPS receiver are unrelated to the NFC link used for contactless payments.

Many MFPs support a Scan-to-Cloud (also called Web Services or Web Connect) feature. After the device is connected to the Internet and the user authenticates, the printer uploads the scanned file directly to the selected cloud-storage account. Other scan destinations such as e-mail, SMB network folders, or USB drives do not perform this direct cloud upload.