Question 1

System initialization — From where do operating systems obtain the system’s total memory information during boot on legacy PCs?

Accepted Answer

Introduction / Context: During early boot, the operating system queries the platform for hardware configuration, including usable memory. On legacy BIOS-based PCs, firmware provides standardized interfaces to report memory maps and sizes. Given Data / Assumptions: Classic BIOS environment (not pure UEFI with ACPI tables only). OS relies on firmware calls and/or SMBIOS/ACPI data. Question asks which component initializes and reports memory totals. Concept / Approach: The BIOS performs POST, detects installed memory, and exposes the results via INT 15h services, E820 memory maps, and SMBIOS/ACPI tables. The OS consumes these to understand total and reserved regions of RAM before establishing its own memory manager. Step-by-Step Solution: BIOS runs POST and enumerates memory.BIOS publishes memory data through standardized interfaces (e.g., INT 15h/E820, SMBIOS).OS queries BIOS to obtain total/usable memory and region layout.Therefore, the source is the BIOS. Verification / Alternative check: Boot logs of many OSes show calls to firmware memory map services. UEFI successors use similar concepts via UEFI Boot Services and ACPI tables. Why Other Options Are Wrong: The CPU does not inventory RAM; RAM cannot self-report; “ROM” is too generic—BIOS is the specific firmware entity responsible. Common Pitfalls: Confusing CMOS with BIOS roles; assuming the OS magically knows memory without firmware or probing. Final Answer: BIOS (firmware reports memory/SMBIOS/INT 15h services).

Question 2

PC bus standards — What does the acronym EISA stand for?

Accepted Answer

Introduction / Context: EISA is a legacy 32-bit expansion bus introduced to succeed ISA in servers and high-end PCs. Knowing full forms of classic acronyms aids in interpreting documentation and troubleshooting expansion compatibility. Given Data / Assumptions: We are referring to the historical PC hardware standard from the late 1980s/early 1990s. Acronym expansion must match the official name. Concept / Approach: EISA literally expands to Extended Industry Standard Architecture. Alternatives like “Expanded” or “Enhanced” are common mis-remembrances but are not the formal name. Step-by-Step Solution: Identify the correct expansion: Extended Industry Standard Architecture.Reject near-synonyms that are historically inaccurate.Select option that matches exactly. Verification / Alternative check: Contemporary vendor literature and standards lists confirm the wording “Extended.” Why Other Options Are Wrong: “Expanded” and “Enhanced” are incorrect and would refer to different concepts. “Electronics” is also incorrect. “All of the above” cannot be true if only one is correct. Common Pitfalls: Confusing EISA with “Enhanced ISA” marketing terms used loosely for other upgrades or with VLB/PCI evolution. Final Answer: Extended Industry Standard Architecture.

Question 3

ISA/AT architecture — How many DMA channels does a standard AT-class PC provide (combined 8-bit and 16-bit controllers)?

Accepted Answer

Introduction / Context: Direct Memory Access (DMA) channels enable devices to transfer data to/from memory without heavy CPU involvement. AT-class systems combined two DMA controllers to support both 8-bit and 16-bit transfers. Given Data / Assumptions: Legacy ISA/AT architecture with cascaded DMA controllers. Counting all channels, including the cascade line. Standard IBM-AT mapping. Concept / Approach: The original PC/XT used an 8237 DMA controller with four channels (0–3). The AT added a second controller for 16-bit DMA (5–7), with channel 4 used for cascading, yielding eight numbered channels in total (0–7). Step-by-Step Solution: List 8-bit DMA: channels 0–3.List 16-bit DMA: channels 5–7 (channel 4 is cascade between controllers).Total channel numbers present: eight (0 through 7).Therefore, the AT machine has 8 DMA channels. Verification / Alternative check: Hardware references and OS device settings from the era enumerate these channels explicitly. Many sound cards and SCSI cards used 5, 6, or 7. Why Other Options Are Wrong: 3 and 4 correspond to subsets; 7 ignores the cascade channel’s presence in the numbering; “None” is incorrect. Common Pitfalls: Confusing the number of “usable” channels with the total numbered channels; forgetting that channel 4 is reserved for cascading. Final Answer: 8.

Question 4

Power supply service — If the bearing in a PSU cooling fan fails, what is the recommended component to replace?

Accepted Answer

Introduction / Context: A failing power supply fan can lead to overheating, instability, and safety hazards. Servicing internal PSU components exposes technicians to dangerous voltages and stored energy, even when unplugged. Given Data / Assumptions: Typical consumer/office ATX-style PSU with sealed enclosure. Fan bearing failure is diagnosed (noise, wobble, stalling). Standard safety practices are followed. Concept / Approach: Industry best practice is to replace the entire PSU rather than open and repair it. Inside a PSU, capacitors can retain lethal charge. Replacing only the fan or bearing requires opening the case, which most vendors discourage and which voids safety certifications. A new PSU restores safety compliance and reliability. Step-by-Step Solution: Confirm fan bearing failure symptoms.Evaluate risk of internal repair versus replacement.Select full PSU replacement to maintain safety and reliability ratings.Verify correct wattage, connectors, and efficiency rating for the replacement unit. Verification / Alternative check: Vendor service policies and A+-style training emphasize replacing the PSU rather than servicing internals in the field. Why Other Options Are Wrong: Replacing only the fan or bearing requires opening the PSU and is hazardous; replacing the case accomplishes nothing; “None” is incorrect because replacing the PSU is the recommended practice. Common Pitfalls: Running systems with a failing fan, attempting a DIY fan swap without proper discharge tools, and choosing a low-quality replacement with inadequate protections. Final Answer: Replace the entire power supply unit (PSU).

Question 5

Standard VGA Resolution  In classic PC graphics terminology, what is the native pixel resolution commonly associated with the standard VGA display mode?

Accepted Answer

Introduction / Context: The Video Graphics Array (VGA) standard defined baseline display capabilities for early PCs and remains a reference point in troubleshooting, compatibility modes, and embedded systems. Knowing the canonical resolution helps when configuring BIOS screens, safe-mode video, and legacy hardware. Given Data / Assumptions: We are referring to the standard VGA graphics mode defined by IBM and widely supported. “Native” here means the most recognized base graphics resolution tied to the VGA standard. Interlaced or extended Super VGA (SVGA) modes are excluded. Concept / Approach: Standard VGA provides multiple text and graphics modes. The best-known graphics mode is 640 by 480 pixels at 60 Hz, originally with a 16-color palette in the basic spec. This resolution became the de facto safe mode for boot screens and OS fallbacks because almost all hardware can generate it reliably. Step-by-Step Solution: Identify common VGA modes: 320 x 200 (13h) for 256-color games, and 640 x 480 for general graphics.Recognize that “standard VGA” commonly denotes 640 x 480.Exclude higher SVGA resolutions (for example, 800 x 600, 1024 x 768) that require VESA extensions.Select 640 x 480 as the standard VGA resolution. Verification / Alternative check: Motherboard BIOS and OS “VGA mode” fallbacks consistently use 640 x 480, confirming this as the accepted baseline. Why Other Options Are Wrong: 648 x 320 and 680 x 440 are nonstandard values. 1024 x 786 is a misspelling/mistake of 1024 x 768 (SVGA), not standard VGA. “None of the above” is unnecessary since 640 x 480 is correct. Common Pitfalls: Confusing VGA with SVGA or with DOS game mode 320 x 200 (Mode 13h). Ensure you distinguish “standard VGA” from later extended modes. Final Answer: 640 x 480

Question 6

Preventing Data Corruption from Power Loss  Which device is specifically designed to keep a computer powered during short outages so that data is not corrupted?

Accepted Answer

Introduction / Context: Unexpected power interruptions can corrupt open files, damage file systems, and interrupt critical updates. Understanding which protective device actually supplies temporary power is essential for system reliability and data integrity. Given Data / Assumptions: The goal is to prevent power interruption, not merely voltage spikes. Short-term ride-through power and orderly shutdown capability are desired. Typical office/home environments with desktop PCs and servers are considered. Concept / Approach: An Uninterruptible Power Supply (UPS) contains batteries and power electronics that instantly provide AC power when mains fail. This keeps the computer running long enough to save work or perform an automatic, graceful shutdown. Surge protectors only clamp transient spikes; grounding ensures safety and noise control but does not supply power; “sag protectors” mitigate brownouts but are uncommon and typically do not provide full backup energy. Step-by-Step Solution: Identify the requirement: maintain power during outages.Map devices to functions: UPS = energy storage + inverter output.Confirm that surge strips and grounding do not deliver stored energy.Select UPS as the only option that prevents interruptions. Verification / Alternative check: UPS units advertise runtime in minutes at specified loads, and management software logs switchover events, confirming continuous operation through brief outages. Why Other Options Are Wrong: Proper grounding improves safety but cannot sustain power. Surge protectors clamp spikes only. “Sag protectors” or line conditioners reduce dips but typically lack batteries. “None of the above” is incorrect because a UPS directly addresses the requirement. Common Pitfalls: Assuming a surge strip alone is adequate or ignoring battery maintenance in UPS units. Replace batteries per manufacturer guidance. Final Answer: UPS

Question 7

Proper Storage of 5¼-inch Floppy Diskettes  When not in use, how should 5¼-inch diskettes be stored to minimize dust, abrasion, and magnetic damage?

Accepted Answer

Introduction / Context: Although legacy, 5¼-inch magnetic diskettes are still encountered in archival settings and in the restoration of vintage systems. Proper storage practices reduce data loss and extend media life for recovery tasks. Given Data / Assumptions: The medium is a flexible magnetic disk inside a thin jacket with an exposed window. Environmental threats include dust, fingerprints, abrasion, moisture, and magnetic fields. Media will be stored for extended periods between uses. Concept / Approach: Protective paper sleeves are designed to cover the diskette jacket and shield the head window from dust and scratches. They also reduce static attraction of debris. Storing diskettes inside sleeves, in a cool, dry place away from magnetic sources, is the recommended best practice from manufacturer guidelines. Step-by-Step Solution: Place each diskette into its fitted protective sleeve immediately after use.Store flat in labeled boxes, away from magnets and sunlight.Avoid plastic bags that trap moisture and static.Never leave diskettes in drives; heads and doors can deform the jacket over time. Verification / Alternative check: Media longevity studies and vendor handling guides consistently recommend sleeves plus controlled environment to reduce head clogging and read errors. Why Other Options Are Wrong: Plastic bags promote static and condensation. Upright shelf storage without sleeves exposes the head window. Leaving a disk in the drive risks warping and particulate contamination. “None of the above” is incorrect because sleeves are specifically designed for storage. Common Pitfalls: Writing on the diskette jacket with hard-tip pens (causes abrasion) or storing near speakers/transformers that can erase data. Final Answer: Their protective sleeves

Question 8

Identifying an Input/Output FRU  Which of the following field-replaceable units (FRUs) is best categorized as an input/output device because it handles both inbound and outbound data?

Accepted Answer

Introduction / Context: Field Replaceable Units (FRUs) are components designed for quick swap in service situations. Classifying a part as input/output (I/O) helps technicians allocate interrupts, DMA (where relevant), and drivers during troubleshooting. Given Data / Assumptions: Video boards primarily output display data to a monitor. A SCSI host adapter interfaces storage and peripherals, moving data in and out. CPUs execute code but are not generally categorized as I/O interfaces. Concept / Approach: An I/O FRU is one that bridges the system bus and external/peripheral buses, transferring data bi-directionally. The SCSI host adapter fits this definition: it manages command and data phases with attached devices, performing reads and writes. Video boards are output-centric; CPUs are processors, not I/O interfaces. Step-by-Step Solution: Identify which devices act as data gateways (host adapters, NICs, HBAs).Note that SCSI HBA controls both read and write operations for disks/tapes/scanners.Conclude it is an I/O FRU by function and service practice. Verification / Alternative check: Driver categories in operating systems list SCSI HBAs under storage controllers (I/O). Service manuals describe replacing HBAs as FRU operations to restore I/O paths. Why Other Options Are Wrong: Video boards predominantly output; they are not general I/O bridges. CPUs are compute elements and not classified as FRU I/O devices. “All of the above” and “None of the above” are therefore incorrect. Common Pitfalls: Confusing a device that moves data (CPU) with a device that interfaces buses (I/O). The distinguishing feature is external/peripheral bus control. Final Answer: SCSI host adapter

Question 9

Understanding ATAPI Compliance  ATAPI compliance most directly refers to support for which class of devices on the ATA interface?

Accepted Answer

Introduction / Context: ATAPI stands for ATA Packet Interface. It extends the ATA (IDE) command set so non-hard-disk devices—such as optical drives and tape drives—can communicate over the same physical interface. Recognizing what ATAPI covers helps in cabling and BIOS configuration. Given Data / Assumptions: ATA alone was originally optimized for hard disks. ATAPI adds packet commands for broader device classes. Examples include CD-ROM, DVD, and some removable storage devices. Concept / Approach: While “CDROM” is a classic example of an ATAPI device, ATAPI is not limited to optical drives; it encompasses multiple types of mass storage that use packetized commands over ATA. Bus mastering is a separate concept related to DMA and does not define ATAPI compliance by itself. Thus the most accurate general choice is “mass storage device.” Step-by-Step Solution: Recall definition: ATAPI = ATA Packet Interface.Recognize it enables non-HDD storage (optical, tape) over ATA.Select the broad category “mass storage device” rather than a single example like CD-ROM. Verification / Alternative check: Device manager entries and drive specs identify ATAPI for optical drives and other packet-based storage peripherals, confirming its general mass-storage scope. Why Other Options Are Wrong: “CDROM” is too narrow; ATAPI covers more. “Bus mastering” is unrelated to the definition. “All of the above” becomes incorrect because bus mastering does not define ATAPI. Common Pitfalls: Equating ATAPI solely with CD-ROMs or assuming it implies any specific DMA/bus mastering feature. Final Answer: Mass storage device

Question 10

Serial Hardware Flow Control  True or False: Before sending data, a modem asserts the RTS (Request To Send) signal.

Accepted Answer

Introduction / Context: Hardware flow control on RS-232 links uses handshake signals to coordinate transmission between a Data Terminal Equipment (DTE, typically the computer) and Data Communication Equipment (DCE, typically the modem). Distinguishing which side asserts which signal prevents miswiring and configuration errors. Given Data / Assumptions: Standard RS-232 naming: RTS = Request To Send; CTS = Clear To Send. DTE is the initiator of RTS; DCE responds with CTS. We consider classic modem connections, not null-modem special cases. Concept / Approach: In RS-232, the computer (DTE) raises RTS to request permission to transmit. The modem (DCE) asserts CTS when it is ready to accept the data. Therefore, the statement “a modem sends RTS” in advance of transmission is false; the modem responds with CTS rather than initiating with RTS. Step-by-Step Solution: Identify device roles: PC → DTE, Modem → DCE.Recall signal responsibilities: DTE asserts RTS; DCE asserts CTS.Conclude the statement is false since the modem does not send RTS. Verification / Alternative check: Serial cable pinouts and modem AT command guides list CTS as a modem output and RTS as a DTE output, confirming the direction of control. Why Other Options Are Wrong: “True” would invert the signal roles. Blank or unspecified options are irrelevant. Common Pitfalls: Confusing hardware flow control (RTS/CTS) with software flow control (XON/XOFF), or mixing DTE/DCE terminology. Final Answer: False

Question 11

Field-Replaceable Units (FRUs)  Which of the following is NOT typically classified as a field replaceable unit in standard PC service practice?

Accepted Answer

Introduction / Context: FRUs are parts intended to be swapped quickly in the field without board-level repair. Identifying what is and is not a FRU streamlines spare parts inventory and service procedures. Given Data / Assumptions: Typical FRUs include plug-in cards, power supplies, memory modules, storage devices, and some socketed ROMs. Structural elements (cases/chassis) are not commonly stocked as FRUs for rapid replacement, except in depot or warranty rebuild scenarios. We refer to common PC service contexts. Concept / Approach: System ROM chips (or modules) and video controllers are replaceable components; power supplies are classic FRUs. By contrast, the system chassis is a mechanical enclosure; while it can be replaced, it is not typically a quick-swap FRU in field service due to labor, wiring, and regulatory labeling considerations. Step-by-Step Solution: List common FRUs versus mechanical assemblies.Note that PSU, ROMs, and video cards are service-replaceable.Identify the chassis as the non-FRU among the options. Verification / Alternative check: Service manuals and parts catalogs classify PSUs, cards, and modules as FRUs; chassis typically falls under mechanical assemblies replaced in depot service rather than quick field swaps. Why Other Options Are Wrong: System ROM, power supply, and video controller are all routinely replaced in the field. “None of the above” is therefore incorrect. Common Pitfalls: Assuming that because an item can be replaced, it is automatically a FRU. FRU implies standard stocking and streamlined replacement procedures. Final Answer: System chasis

Question 12

Classifying a SCSI Host Adapter  A SCSI host adapter card is best categorized as which type of field-replaceable unit (FRU)?

Accepted Answer

Introduction / Context: SCSI host adapters (HBAs) connect the system bus to SCSI devices such as disks, tapes, and scanners. Correctly identifying their category simplifies inventory and replacement decisions in the field. Given Data / Assumptions: SCSI HBAs are plug-in expansion cards. They provide input/output services between the host and peripherals. They are replaced as discrete cards during service. Concept / Approach: By function and form, a SCSI HBA is an I/O controller card. It is not a CPU (processor), not a display adapter (video card), and not a storage device (hard drive). Therefore, classifying it as an I/O card is accurate and aligns with service documentation. Step-by-Step Solution: Determine what the device interfaces: host bus ↔ SCSI bus.Map that role to the I/O category.Select “I/O card” as the FRU type. Verification / Alternative check: OS device managers list SCSI controllers under “Storage controllers” or “SCSI/RAID controllers,” confirming their I/O function and swappable nature. Why Other Options Are Wrong: CPU, video card, and hard drive are distinct classes. The SCSI adapter is none of these. Common Pitfalls: Confusing an I/O controller with a storage device because both relate to disks; the adapter controls, the drive stores. Final Answer: I/O card

Question 13

Perceptibility of Static Discharge  A human typically cannot feel (perceive) a static electric discharge as low as which of the following voltage levels?

Accepted Answer

Introduction / Context: Electrostatic discharge (ESD) can damage electronic components at voltages far below the threshold of human perception. Understanding perception thresholds helps explain why unseen ESD events still harm sensitive parts. Given Data / Assumptions: Human perception of a spark typically begins around 2 kV to 3 kV in normal humidity. Electronics can be damaged by discharges as low as a few tens to hundreds of volts. We are comparing options that include very low and very high voltages. Concept / Approach: Because people usually do not feel discharges until the voltage is in the kilovolt range, any small value like 50 V is far below the tactile threshold. Thus, while 50 V ESD can harm ICs, a person will not notice it. The question asks for a level that a human cannot feel; the smallest value offered is the clearest correct choice in that context. Step-by-Step Solution: Recall perception threshold: approximately 2,000–3,000 V under typical conditions.Recognize that 50 V is well below that threshold.Select 50 V as a level a human cannot feel. Verification / Alternative check: ESD control literature emphasizes damage at 100 V or less to MOS devices, while humans perceive only much higher voltages. Why Other Options Are Wrong: 200 V may still be imperceptible but is higher than necessary; the best answer is the lowest value. 2000 V, 10000 V, and 50000 V are easily felt and often seen/heard. Common Pitfalls: Assuming that if you cannot feel ESD it cannot cause damage. Sensitive components can be harmed by imperceptible discharges. Final Answer: 50

Question 14

Protecting Against Power Interruptions  Which device specifically supplies temporary backup power to prevent interruptions that may corrupt data?

Accepted Answer

Introduction / Context: Data corruption often occurs when power fails during writes or updates. The correct protective device must provide actual energy during outages, not just noise suppression, so that systems can continue operating or shut down gracefully. Given Data / Assumptions: We need to bridge short power losses to avoid abrupt shutdowns. The solution should be functionally equivalent to an Uninterruptible Power Supply (UPS). Other options may protect against surges or be irrelevant to power continuity. Concept / Approach: A battery back-up unit (UPS) contains batteries and inverter circuitry to deliver AC power during an outage. This prevents immediate shutdown and data loss. Surge protectors clamp voltage spikes but do not power equipment. Extra memory modules or vague “data guard” labels do not address the root problem, and turning off AC power obviously does not help. Step-by-Step Solution: Identify requirement: uninterrupted power for a limited time.Map device capabilities: only a battery-backed unit provides energy.Select the option that corresponds to a UPS. Verification / Alternative check: UPS specifications list runtime and load ratings; many include USB signaling for automatic shutdown, confirming their role in preventing corruption. Why Other Options Are Wrong: Surge protectors lack energy storage. Memory quantity has no effect on power continuity. “Data guard system” is not a standard power device, and turning power off does nothing to protect data. Common Pitfalls: Confusing surge suppression with power backup. Always ensure batteries are maintained to keep backup effective. Final Answer: Battery back-up unit

Question 15

Electrostatic discharge (ESD) safety: An ESD wrist strap is primarily designed to protect what during computer service—PC components, service technicians, or both?

Accepted Answer

Introduction / Context: Electrostatic discharge (ESD) is a major cause of latent and catastrophic failures in semiconductor devices. An ESD wrist strap provides a controlled, safe path for charge to bleed to ground while you handle circuit boards. This item tests whether you know the main protection target of ESD controls during PC repair. Given Data / Assumptions: The technician wears a grounded ESD wrist strap while handling printed circuit boards. Standard straps include a high-value series resistor (about 1 MΩ) for safety. The question asks what the strap is designed to protect, not what else it may incidentally benefit. Concept / Approach: The primary purpose of an ESD wrist strap is to protect sensitive electronic components (PC components) from static damage by equalizing potential between the technician and the device. While the strap's resistor also limits fault current to protect the person, the design goal in electronics work is component protection. Therefore, the best single answer is the protection of PC components. Step-by-Step Solution: Identify ultimate objective of ESD control in electronics servicing: preserve component integrity.Recognize that wrist straps bleed static charge gradually to ground.Note that the resistor is a safety feature, but not the primary purpose.Select the option that names the protected target: PC components. Verification / Alternative check: Manufacturer service guides and IPC/ESD standards emphasize component protection as the justification for ESD programs. Human safety is addressed by the series resistor but is not the core purpose statement. Why Other Options Are Wrong: Service Technicians: The resistor improves safety, but the strap exists to protect electronics. All of the above: Overstates the design intent; primary goal is component protection. None of the above: Incorrect; components are protected. Common Pitfalls: Clipping to ungrounded metal, bypassing the resistor, or wearing the strap over insulating clothing defeats protection. Final Answer: PC Components

Question 16

UPS usage best practices: Which device should not be plugged into a standard uninterruptible power supply (UPS)?

Accepted Answer

Introduction / Context: Uninterruptible power supplies provide battery-backed power and filtering for critical electronics. However, certain peripherals draw large inrush and sustained currents that can overload or rapidly deplete a standard UPS, compromising protection for truly critical devices. Given Data / Assumptions: Typical office UPS units are sized for PCs, monitors, networking gear, and external modems. Laser printers have fusers that heat up and draw high peak currents. The question refers to a standard (not high-capacity) UPS. Concept / Approach: Laser printers' fuser assemblies consume significant power and can cause UPS overloads, voltage dips, or frequent battery drain. Best practice is to plug laser printers directly into a surge protector (not the battery-backed outlets) unless a UPS is explicitly rated for such loads. Monitors, modems, and ink-jet printers typically fall within UPS capacity and do not cause large inrush spikes like a fuser does. Step-by-Step Solution: Identify the peripheral with the highest inrush/steady load: laser printer.Recall that standard UPS receptacles are not intended for high-wattage heating elements.Choose the device that should not be on a standard UPS: laser printer. Verification / Alternative check: UPS vendor manuals warn against connecting laser printers to battery-backed outlets. Nameplate ratings for fusers confirm high VA draw compared to PCs or monitors. Why Other Options Are Wrong: Monitor, ink-jet printer, and external modem normally operate within UPS limits and benefit from backup and filtering. Common Pitfalls: Plugging a laser printer into battery-backed outlets causes nuisance trips and reduces runtime for critical equipment. Final Answer: laser printer

Question 17

Basic hardware diagnostics: When testing a typical small computer speaker with an ohmmeter, what resistance (in ohms) should you expect to read?

Accepted Answer

Introduction / Context: PC case speakers and many small speakers used for basic beeps are rated by their nominal impedance. Measuring with an ohmmeter provides an approximate check for open or shorted coils during quick diagnostics. Given Data / Assumptions: We are checking a small speaker typical of PC enclosures. Common nominal impedances are 4 Ω, 8 Ω, or 16 Ω. An ohmmeter reading near the nominal impedance indicates a healthy voice coil. Concept / Approach: A proper speaker shows a finite, low resistance corresponding roughly to its impedance rating (DC resistance is usually slightly lower than the rated AC impedance). Zero ohms indicates a shorted coil. Infinity (unlimited) indicates an open coil. Negative resistance is physically meaningless in this context. Of the options given, 16 Ω is the realistic healthy reading for a 16-ohm speaker and represents the only plausible choice. Step-by-Step Solution: Set the meter to a suitable low-ohms range.Measure across the speaker terminals with the speaker disconnected.Confirm a finite value near the nominal impedance (for example, around 12–16 Ω for a 16-Ω speaker).Conclude the speaker is good if the reading is close to nominal and stable. Verification / Alternative check: Brief audio test or continuity tone confirms the coil is intact; visual inspection can reveal burned windings. Why Other Options Are Wrong: 0 Ω indicates a short; unlimited Ω indicates an open; negative values are not valid with a passive resistor-like device. Common Pitfalls: Measuring in-circuit (parallel paths change the reading) or using the wrong meter range. Final Answer: 16 Ohms

Question 18

Mobile device basics: What is the most common direct, short-range communication method from one PDA to another PDA?

Accepted Answer

Introduction / Context: Personal Digital Assistants (PDAs) and early handhelds often exchanged data peer-to-peer without cables. Knowing the common short-range method used historically helps in maintaining or migrating legacy devices and data. Given Data / Assumptions: Context is classic PDA-to-PDA transfer (contacts, calendar, small files). Devices are in close proximity and likely line-of-sight. No docking cradle or host computer is involved. Concept / Approach: Infrared (IR), particularly IrDA (Infrared Data Association) standards, was the de facto method for PDA beaming. It provided simple, cable-free, line-of-sight exchange. USB and IEEE 1394 are host-centric wired buses, not typical peer-to-peer between standalone PDAs. RS-232 could be used with serial cables and cradles, but not as the main hand-held-to-hand-held wireless method. Step-by-Step Solution: Identify PDA-to-PDA requirement: wireless, short-range, ad hoc.Match to common historical tech: IrDA (IR).Reject cabled host buses (USB, IEEE 1394) and legacy serial cabling (RS-232) for this use case.Select IR. Verification / Alternative check: Device manuals and OS menus often include a “Beam” or “Send via IR” option for contacts and memos. Why Other Options Are Wrong: USB/IEEE 1394 need a host; RS-232 needs a cable and is not the common user workflow for PDA-to-PDA. Common Pitfalls: Blocking the IR window or misaligning devices prevents discovery; ambient sunlight can interfere. Final Answer: IR

Question 19

Telecom acronyms: ISDN stands for which of the following?

Accepted Answer

Introduction / Context: ISDN is a foundational telecommunications standard that provided digital end-to-end connectivity long before modern broadband. Technicians frequently encounter the term in legacy voice/data integrations and exam contexts. Given Data / Assumptions: Acronym identification question. Focus on the exact expansion of ISDN. Concept / Approach: ISDN expands to integrated services digital network, describing consolidated digital services (voice, data, signaling) over the same access line. The other options are nonsense phrases. Step-by-Step Solution: Recall the standard expansion of ISDN.Match it to the provided options.Select the correct phrase: integrated services digital network. Verification / Alternative check: Telecom texts and standards (e.g., ITU-T) use this exact expansion. Why Other Options Are Wrong: They are incorrect fabrications and do not describe telecommunications. Common Pitfalls: Confusing ISDN with DSL; they are different technologies and eras. Final Answer: integrated services digital network

Question 20

PCMCIA / PC Card hardware: Which PC Card (PCMCIA) slot type supports inserting a hard disk drive card?

Accepted Answer

Introduction / Context: Laptops of the PCMCIA era supported several physical card thicknesses. Mechanical form factor determined what devices could be inserted, including network cards, modems, flash storage, and miniature hard drives. Knowing the correct slot type avoids insertion damage and compatibility issues. Given Data / Assumptions: Type I, II, and III PC Cards share the same connector but differ in thickness. Miniature hard disk PC Cards require more thickness than memory/modem cards. Concept / Approach: Type I is 3.3 mm (usually memory), Type II is 5 mm (modems, NICs), and Type III is 10.5 mm to accommodate hard drives. Therefore, a hard drive PC Card requires a Type III slot (or a bay that can accept a Type III card). Step-by-Step Solution: Identify the device: hard disk PC Card.Match to slot thickness that physically fits: Type III.Select Type III as the supporting slot. Verification / Alternative check: Laptop manuals list supported card types; Type III bays are visibly deeper and sometimes occupy two Type II spaces. Why Other Options Are Wrong: Type I and II are too thin for HDD mechanics; Type IV is nonstandard in classic PCMCIA. Common Pitfalls: Forcing a thicker card into a thin slot can damage the laptop or card eject mechanism. Final Answer: type III

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