Question 1

Which statement best describes a key characteristic of a multiprogramming operating system in which CPU time is shared among jobs?

Accepted Answer

Introduction / Context: Multiprogramming is an operating system technique that keeps multiple jobs in memory and switches the CPU among them to improve utilization and responsiveness. It is foundational to time-sharing and modern multitasking, allowing many programs to appear to make progress even on a single processor core. Given Data / Assumptions: A single CPU can switch rapidly among multiple ready processes. Context switching creates the illusion of simultaneous progress. True simultaneous instruction execution requires multiple CPUs or cores, which is not a requirement for multiprogramming. Concept / Approach: Multiprogramming emphasizes concurrency (interleaving) rather than parallelism. The scheduler selects which process runs next, using policies like round-robin, priority, or shortest job first. While multi-CPU systems can execute instructions in parallel, multiprogramming does not mandate multiple processors; it simply requires the OS to manage multiple runnable jobs and switch among them efficiently. Step-by-Step Solution: Define concurrency: multiple programs make progress over time through interleaved execution. Map to multiprogramming: jobs remain ready, and the OS schedules CPU slices for each. Eliminate strict simultaneity on one CPU: physically impossible without multiple cores. Conclude that the best description is “concurrent processing of two or more programs by interleaving on one CPU.” Verification / Alternative check: Historical time-sharing systems (e.g., on mainframes and minicomputers) implemented multiprogramming well before symmetric multiprocessing was common. Modern desktops still rely on this concept even when multiple cores are present—each core also multiprograms among threads. Why Other Options Are Wrong: (a) Simultaneous instruction execution on one CPU is not possible; it is time-sliced. (c) Multiple CPUs are not required for multiprogramming; they enable parallelism, not mere concurrency. (d) “All of the above” fails because (a) and (c) are not accurate requirements. (e) Not applicable because a correct statement exists in (b). Common Pitfalls: Confusing concurrency (interleaving) with parallelism (true simultaneity); assuming that “multi-” in multiprogramming implies multiple CPUs; neglecting the role of context switching and CPU scheduling policy. Final Answer: Concurrent processing of two or more programs by interleaving their execution on one CPU

Question 2

In troubleshooting, you can reach a host by its IP address but not by its name. Which factor is most likely the cause of the name-based communication failure?

Accepted Answer

Introduction / Context: When connectivity by IP works but name lookups fail, the network path is usually fine. The problem instead lies with name resolution—how a textual name maps to an IP address. Understanding typical name sources helps quickly narrow the root cause in Microsoft, Linux, and mixed environments. Given Data / Assumptions: Pinging or connecting via raw IP succeeds. Attempting to reach the same host by its name fails or resolves incorrectly. Name resolution may rely on DNS, WINS/NetBIOS, mDNS, or local static files like hosts/LMHOSTS. Concept / Approach: Name resolution is a separate step preceding connection. If the IP path is good, then DNS records (A/AAAA), NetBIOS/WINS entries, or static mappings may be missing, stale, or misconfigured. For legacy Windows name lookups, LMHOSTS/WINS can override DNS; on Unix-like systems, /etc/hosts or nsswitch.conf order can affect outcomes. Thus, incorrect or missing entries in these static or server-side databases commonly cause “name works for some, not others” scenarios. Step-by-Step Solution: Verify that direct IP connectivity succeeds → confirms routing and layer-3 path. Attempt name resolution (nslookup/dig/getent/nbtstat) → identify failures or wrong answers. Inspect DNS zone entries, WINS registrations, and local hosts/LMHOSTS files for stale or conflicting mappings. Correct the faulty record or flush caches to restore name-based connectivity. Verification / Alternative check: Clearing resolver caches (ipconfig /flushdns, systemd-resolved, or browser cache) often fixes transient issues. Packet captures show DNS queries leaving the client and the responses (NXDOMAIN, SERVFAIL, or wrong IP), pinpointing the database error rather than a routing problem. Why Other Options Are Wrong: The IP address itself: connectivity by IP is already proven to work. Subnet mask: would affect IP reachability, not just name resolution. Default gateway: misconfiguration would break IP paths, not only names. MTU size: impacts fragmentation/throughput, not basic name mapping. Common Pitfalls: Assuming firewall rules selectively block DNS but not application traffic; overlooking split-horizon DNS where internal/external names differ; forgetting that VPN DNS settings can override local resolvers. Final Answer: Static name sources such as an LMHOSTS file or a DNS database entry

Question 3

Brad administers a small office network. He wants a setup that stays simple yet secure, lets users retain full control over their own data, and still allows easy sharing within the office. The staff have excellent networking knowledge. Which network…

Accepted Answer

Introduction / Context: Small teams often need file sharing and collaboration without the cost and administrative overhead of dedicated directory services and centralized servers. Choosing the right network model depends on the balance between simplicity, security, control, and staff skill levels. When users want to control their own data directly and are technically adept, a peer-to-peer model is frequently appropriate. Given Data / Assumptions: Small office network with limited infrastructure budget. Desire for simplicity and reasonable security. Users want full control over their local data while sharing selectively. Staff are comfortable managing settings and permissions. Concept / Approach: In a peer-to-peer network, each workstation acts as both a client and a server for specific resources, enforcing permissions locally. This minimizes centralized administration and cost while maintaining user autonomy. With knowledgeable staff, proper local account management, strong passwords, and OS-level sharing controls can achieve a secure environment. In contrast, a server-based or domain model centralizes authentication and policy, which is powerful but more complex and may not match the simplicity requirement. Step-by-Step Solution: Map the requirements: simplicity + user control + sharing → peer-to-peer. Confirm staff skill: excellent knowledge reduces misconfiguration risk. Contrast with server-based/domain: adds complexity and cost for central control not explicitly needed. Select “Peer-to-peer” as the best fit. Verification / Alternative check: Workgroup configurations on modern desktop OSs allow secure sharing via user/group permissions and network discovery settings. For small offices with under ~10–20 users, this arrangement is common and effective when the team is diligent about security hygiene. Why Other Options Are Wrong: Master domain/Server-based: require domain controllers and centralized administration—powerful but opposite of “simple.” Ethernet: describes the link technology, not a network model. Share-level (legacy): dated, weaker security compared to user-level permissions in modern peer-to-peer setups. Common Pitfalls: Underestimating backup needs—peer-to-peer still requires disciplined backups. Also, mixing user-level and share-level permissions inconsistently can cause access confusion. Final Answer: Peer-to-peer

Question 4

Which device links two homogeneous packet-broadcast Local Area Networks (for example, two Ethernet segments) by forwarding frames based on MAC addresses?

Accepted Answer

Introduction / Context: Interconnecting LAN segments can be done at different OSI layers. When the networks are homogeneous (same Layer-2 technology) and you want to forward frames based on MAC addresses while preserving a single Layer-3 subnet, the classic device is a bridge. Modern switches are multiport bridges, performing the same fundamental function with hardware acceleration. Given Data / Assumptions: Two LANs share the same L2 protocol (e.g., Ethernet). Forwarding should occur using MAC learning and filtering. No Layer-3 routing or protocol translation is required. Concept / Approach: A bridge learns source MAC addresses per port and forwards unknown-unicast, multicast, or broadcast frames accordingly while filtering frames that do not need to cross segments. This reduces collisions (in older shared media) and contains unnecessary traffic. Repeaters/hubs operate at Layer-1, simply regenerating bits, and do not learn MACs. Routers operate at Layer-3 and separate IP subnets. Gateways typically imply protocol translation or higher-layer mediation. Step-by-Step Solution: Identify the requirement: same Layer-2 technology and MAC-based forwarding. Map to device: a bridge (or switch) performs L2 learning and filtering. Exclude repeater/hub (L1) and router/gateway (L3+). Select “Bridge.” Verification / Alternative check: Spanning Tree Protocol (STP) is a Layer-2 control protocol used by bridges/switches to prevent loops—further evidence that bridges are the appropriate L2 interconnect for homogeneous networks. Why Other Options Are Wrong: Repeater/Hub: no MAC learning; simply regenerate and repeat signals. Router: forwards based on IP/subnet; separates broadcast domains. Gateway: often implies heterogeneous protocol translation beyond simple L2 forwarding. Common Pitfalls: Using “gateway” generically to describe any interconnect; forgetting that modern switches are functionally bridges with many ports. Final Answer: Bridge

Question 5

At a Point-of-Sale (POS) terminal, what is the handheld OCR/optical reading unit commonly called when used to scan printed codes or characters?

Accepted Answer

Introduction / Context: Retail and POS environments use optical readers to capture product information quickly at checkout. Early and inexpensive devices were “wand” scanners—pen-like readers that you sweep across printed barcodes or specially formatted OCR characters. Recognizing the customary terminology helps distinguish among optical input devices used with terminals and kiosks. Given Data / Assumptions: The device is handheld and used at POS to read printed information. It uses optical sensing (reflected light) to decode patterns. Terminology focuses on common industry names. Concept / Approach: A wand scanner contains a light source and sensor; as it moves across a barcode or OCR line, it measures reflectance changes to reconstruct bars/spaces or character strokes. The terminal decodes the signal into digits or alphanumeric codes. By contrast, a light pen historically interacted with CRT screens by detecting the raster’s electron beam; a “cursor” is an on-screen pointer, not a hardware scanner; and modern “barcode imagers” are camera-based but not typically referred to as “OCR reading units” in legacy POS wording. Step-by-Step Solution: Identify the POS optical handheld reader category → wand scanner. Confirm it scans printed codes/OCR by contact or close proximity sweep. Differentiate from light pens (screen input) and cursors (UI concept). Select “Wand.” Verification / Alternative check: POS equipment catalogs historically list “wand readers” for barcodes/OCR fonts (e.g., OCR-A/OCR-B on labels). Though modern 2D imagers are common today, the traditional name for the simple optical stick reader remains “wand.” Why Other Options Are Wrong: Light pen: interacts with CRT displays, not printed codes on labels. Cursor: a software pointer; not hardware. All of the above: incorrect because only “wand” matches the POS OCR/barcode reading unit. Barcode imager: technically plausible modern device but not the classic OCR “wand” term used in the question’s context. Common Pitfalls: Assuming any optical input device at POS is a “light pen”; ignoring that the typical handheld legacy reader for printed codes is specifically called a “wand.” Final Answer: Wand

Question 6

In a Local Area Network (LAN), what do we call the computer that provides shared resources (files, printers, applications) and central management for network users?

Accepted Answer

Introduction / Context: LANs rely on systems that make resources available to multiple users and enforce access control. The machine that hosts shared folders, databases, print queues, directory services, or application services is commonly referred to as a network server. Distinguishing it from software (the OS) or services (VPN) avoids conceptual confusion on exams and in design discussions. Given Data / Assumptions: We seek the role of a computer within a LAN. The role includes resource sharing and administrative control. The term should identify the hardware/host role, not a protocol stack or abstract model. Concept / Approach: A network server is a host that offers services to clients: file/print services, web/database hosting, directory and authentication, and sometimes centralized backup. It runs a network operating system that enables these services, but the OS itself is not the “server”—the machine performing the server role is. VPNs provide secure remote connectivity, and OSI is a conceptual model, not a device or role. Step-by-Step Solution: Identify the noun that names the computer providing shared resources → Network Server. Differentiate from software classifications (network operating system) or frameworks (OSI). Exclude VPN which is a tunneling service, not a LAN host role. Select “Network Server.” Verification / Alternative check: Administrative consoles for file and print services, Active Directory/LDAP, and application servers are hosted on servers accessible to many clients—concretely matching the definition of a network server in LANs. Why Other Options Are Wrong: Virtual Private Network: a secure tunneling method, not a physical server role. Network operating system: software that may run on a server, not the machine itself. OSI: a model for understanding layers; not a device or service role. Network client: the consuming endpoint rather than the providing host. Common Pitfalls: Equating the OS with the role; using “server” to mean both hardware and software indiscriminately without recognizing the context of the question. Final Answer: Network Server

Question 7

Within the OSI model, which layer is responsible for creating and recognizing frame boundaries (i.e., framing) on a link between adjacent nodes?

Accepted Answer

Introduction / Context: The OSI model separates networking responsibilities into seven layers. Framing—the process of packaging bits into identifiable units with headers, trailers, and delimiters so that neighbors can detect beginnings and ends—is essential to reliable link-local communication. Knowing which layer performs framing helps distinguish physical signaling from logical link control. Given Data / Assumptions: We are focused on communication between directly connected nodes (adjacent). Framing is about defining frame boundaries and associated control information. Error detection (e.g., CRC) is often part of the same layer’s responsibilities. Concept / Approach: The Data Link layer (Layer 2) handles framing. It encapsulates higher-layer packets into frames with headers and trailers, includes an FCS/CRC for error detection, and manages media access control (MAC). The Physical layer (Layer 1) is responsible for transmitting raw bits as electrical/optical/radio signals but does not define where frames start or end. Network and Transport layers operate on packets/segments above the link level, not on raw frames between adjacent nodes. Step-by-Step Solution: Identify the task: define frame boundaries so receivers can parse units of data. Map to OSI: framing and MAC logic → Data Link layer. Exclude Physical: deals with signaling and bit timing only. Exclude Network/Transport: end-to-end packet/segment delivery above the link. Verification / Alternative check: Examples include Ethernet frames with preamble/SFD, headers, payload, and FCS; HDLC/PPP frames with flags and FCS. All are standardized Data Link layer constructs for framing on point-to-point or shared media. Why Other Options Are Wrong: Physical: no framing; only signal levels, modulation, and timing. Network: routing and logical addressing, not frame delimitation. Transport: reliability and flow control between endpoints, not neighbors. Session: dialog control above Transport; not link framing. Common Pitfalls: Attributing CRC solely to Physical layer; mixing the concept of packets (L3) with frames (L2). Also, assuming preamble is a Physical construct—while transmitted at Layer 1, its framing meaning belongs to Layer 2. Final Answer: Data link layer

Question 8

In Microsoft DHCP administration, what is the specific term used for the defined set of IP addresses that a DHCP server can lease to clients on a given subnet?

Accepted Answer

Introduction / Context: Dynamic Host Configuration Protocol (DHCP) automates IP address assignment so administrators do not have to configure each client manually. In Microsoft Windows Server DHCP, the server's addressable space for a particular subnet is organized using a specific object that defines which IPs are eligible to be leased. This question checks whether you know the precise administrative term used by Microsoft for that defined set of addresses. Given Data / Assumptions: The environment is Microsoft Windows Server DHCP. We are focusing on the defined set of IPs available to lease on a subnet. Terminology varies across vendors; we want Microsoft's canonical term. Concept / Approach: In Windows DHCP, a scope is the fundamental configuration object that specifies the IPv4 network ID, subnet mask, start and end of the usable address range, exclusions, lease duration, and options (such as default gateway and DNS servers). Although many engineers informally say “pool” or “range,” those words describe parts of a scope (the contiguous address range or the general idea of available addresses). In Microsoft's console, however, the formal, manageable unit you create and enable for a subnet is called a scope. Step-by-Step Solution: Identify the platform: Microsoft DHCP on Windows Server.Determine the administrative object that defines leasable addresses: Scope.Confirm that “pool” and “range” are informal or component ideas, not the canonical object name.Select “Scopes” as the correct term. Verification / Alternative check: In the DHCP management console (dhcpmgmt.msc) and documentation, you create a new Scope, specify its address range, optionally configure exclusions and reservations, and activate it. That language confirms the official term as “scope.” Why Other Options Are Wrong: Pools: colloquial and used by some vendors, but not the formal Windows DHCP object name. Ranges: a subsetting concept inside a scope; not the administrative container itself. Notes: metadata, not an address set. None of the above: incorrect because “Scopes” is correct. Common Pitfalls: Mixing cross-vendor terminology; assuming “pool” is universally correct; forgetting that a scope also encapsulates options, lease policies, and exclusions beyond just the start/end IPs. Final Answer: Scopes.

Question 9

In serial interface standards, which of the following is NOT a standard RS-232-C control/handshake signal line?

Accepted Answer

Introduction / Context: RS-232-C is a classic interface standard that specifies electrical characteristics and signal assignments between Data Terminal Equipment (DTE) and Data Communication Equipment (DCE). Knowing the common control and handshake lines is essential when wiring serial links or troubleshooting modem connections. This item asks you to pick the one label that does not belong to the RS-232-C family of well-known signals. Given Data / Assumptions: Common RS-232-C control lines include RTS (Request To Send), CTS (Clear To Send), DSR (Data Set Ready), DTR (Data Terminal Ready), RI (Ring Indicator), and DCD (Carrier Detect). The distractor uses an unfamiliar mnemonic. We are focusing on canonical signal names, not vendor-specific aliases. Concept / Approach: By recalling standard RS-232-C signal mnemonics, you can quickly reject unfamiliar or nonstandard labels. RTS/CTS are used for hardware flow control, DSR indicates the DCE is ready, and other standard pins include DTR, DCD, and RI. “VDR” is not part of the RS-232-C signal set and therefore is the correct choice as the nonstandard entry. Step-by-Step Solution: List typical RS-232-C signals: RTS, CTS, DSR, DTR, DCD, RI, TXD, RXD, GND.Compare each option against this list.Recognize that VDR is not defined in RS-232-C.Select VDR as the nonstandard signal. Verification / Alternative check: Any RS-232-C pinout reference confirms the absence of “VDR” and the presence of RTS, CTS, and DSR among the control lines, reinforcing the identification by elimination. Why Other Options Are Wrong: RTS: standard outbound flow-control request from DTE. CTS: standard inbound permission from DCE to send. DSR: standard DCE-ready status. None of the above: incorrect because one option (VDR) is indeed nonstandard. Common Pitfalls: Confusing DSR with DTR; assuming unfamiliar mnemonics might be vendor extensions; overlooking that RS-232 naming is quite consistent across documentation. Final Answer: VDR.

Question 10

An enterprise anticipating rapid growth in communications capacity may deploy which types of equipment to manage throughput, connectivity, and device access?

Accepted Answer

Introduction / Context: As organizations scale, their networks must handle more users, devices, and data flows. Multiple classes of equipment help aggregate lines, offload protocol work, and coordinate attached devices. This question tests your awareness of common categories of communications gear that enterprises employ to meet increasing demand. Given Data / Assumptions: Requirements include line aggregation, protocol handling, and device coordination. Terms are used in their classical sense from data-communications literature. Modern equivalents (e.g., integrated routers/switches) often subsume several roles. Concept / Approach: A front-end processor historically offloads communication tasks (error control, line handling) from a host. A multiplexer (MUX) combines multiple low-rate inputs onto a higher-capacity line via TDM/FDM/statistical methods. A controller supervises connected terminals or lines, coordinating access and simplifying host interfaces. A concentrator aggregates many low-duty-cycle lines so they can share fewer high-capacity circuits efficiently. Because each device class addresses a different facet of scaling, enterprises frequently use all of them (or their modern equivalents) as needs grow. Step-by-Step Solution: Identify scaling problems: many endpoints, higher throughput, protocol overheads.Map to solutions: front-end offload, multiplexing, centralized control, and line concentration.Acknowledge overlap: modern multiservice platforms integrate these roles.Conclude that all listed categories may be used. Verification / Alternative check: In legacy mainframe and minicomputer environments, front-end processors and controllers were standard; in carrier networks, MUXes and concentrators remain fundamental concepts, now embodied in routers, DSLAMs, and access switches. Why Other Options Are Wrong: Each individual choice solves only part of the problem; no single item fully satisfies diverse scaling needs. All of the above is correct because enterprises may deploy several device types together. Common Pitfalls: Treating “multiplexer” and “concentrator” as synonyms; ignoring that “controller” is a distinct supervisory role; assuming front-end processing is obsolete when in fact it persists inside NICs, offload cards, and router line cards. Final Answer: All of the above.

Question 11

Network-layer identification: which of the following is NOT an example of a network-layer protocol or function (choose the item that belongs to a different OSI layer)?

Accepted Answer

Introduction / Context: The OSI model separates concerns across layers. The network layer (Layer 3) provides logical addressing and routing across multiple links, while the data link layer (Layer 2) ensures reliable transfer over a single link. This question asks you to pick the one item that is clearly not a network-layer protocol or function, emphasizing accurate mapping to OSI layers. Given Data / Assumptions: IP is a canonical network-layer protocol. X.25 defines both a packet layer (network layer) and a link layer (LAPB). “Source routing” is a network-layer concept; “domain naming” belongs to applications, but the option pairs them in a historical context. Concept / Approach: Map each entry to the OSI layer it best represents. IP is firmly Layer 3. X.25 PLP (Packet Layer Protocol) implements virtual circuits at Layer 3. X.25 Level 2 (LAPB) is Link Access Procedure, Balanced—a Layer 2 (data link) protocol, not Layer 3. The “source routing and domain naming – Usenet” phrasing mixes layers, but source routing itself is a network-layer feature; the presence of an application concept in the same phrase does not change the fact that source routing maps to Layer 3. The one unambiguous non–Layer 3 entry is LAPB. Step-by-Step Solution: Classify IP: network layer (routing and forwarding across subnets).Classify X.25 PLP: network layer (virtual circuit packet service).Classify X.25 Level 2 (LAPB): data link layer (framing, error control on a single link).Resolve the mixed entry: source routing pertains to Layer 3 behavior.Choose the non-network-layer item: LAPB (X.25 Level 2). Verification / Alternative check: Any protocol reference shows LAPB as ISO data link layer; PLP is the X.25 network layer. IP remains the Internet’s Layer 3 protocol, confirming the separation. Why Other Options Are Wrong: IP: quintessential Layer 3. X.25 PLP: defined as the packet (network) layer of X.25. Source routing and domain naming: includes a Layer-3 concept (source routing); the item is not purely non-network-layer. None of the above: incorrect because one item is definitely not Layer 3. Common Pitfalls: Confusing X.25's layered components; assuming that application-layer naming invalidates the presence of a network-layer function; forgetting that LAPB is link-layer framing and error control only. Final Answer: X.25 Level 2 (LAPB) – ISO.

Question 12

On classic 10 Mbps Ethernet (IEEE 802.3) using the 5-4-3 rule, what is the maximum number of repeaters allowed between any two nodes on a collision domain?

Accepted Answer

Introduction / Context: Early shared-media Ethernet imposed physical-layer limits to ensure that collision detection worked reliably and that signals maintained integrity over distance. The well-known “5-4-3” guideline constrained the number of segments and repeaters that could exist between any two stations. This question asks for the maximum number of repeaters permitted between hosts on a single collision domain under that rule. Given Data / Assumptions: Classic 10 Mbps Ethernet (10BASE5/10BASE2/10BASE-T in shared modes). Shared collision domain with repeaters (hubs) extending reach. Use of the 5-4-3 rule (five segments, four repeaters, three populated segments). Concept / Approach: The 5-4-3 rule states: between any two stations, you may have at most five segments connected by four repeaters, and of those segments no more than three may be populated (have active hosts). Limiting repeaters controls end-to-end propagation delay so that collisions are detected within a slot time, preserving CSMA/CD's assumptions. Therefore, the answer is four repeaters maximum between two nodes in the collision domain. Step-by-Step Solution: Recall the guideline: 5 segments, 4 repeaters, 3 populated segments.Map “maximum repeaters between two nodes” to the middle number: 4 repeaters.Confirm this maintains timing needed for collision detection.Choose “Four.” Verification / Alternative check: Ethernet design texts and vendor deployment guides for coax and hub-based topologies reiterate the 5-4-3 rule as the practical limit for 10 Mbps shared Ethernet, aligning with the slot time and propagation constraints of CSMA/CD. Why Other Options Are Wrong: Five / Six: exceed the repeater limit; would break timing budgets. Two / Three: stricter than necessary; acceptable but not the maximum permitted by the rule. Common Pitfalls: Misremembering which number corresponds to repeaters vs. segments; applying the rule to switched, full-duplex Ethernet (it does not apply there); assuming the same limits for Fast/Gigabit Ethernet, which use different constraints. Final Answer: Four.

Question 13

In digital communications, what does the modulation process accomplish at the transmitter?

Accepted Answer

Introduction / Context: Many physical media—radio, coaxial cable carrying RF, satellite links—carry information using analog carriers. To send binary data across such media efficiently, a transmitter modifies a sinusoidal carrier's properties (amplitude, frequency, or phase) according to the digital symbols. This transmitter-side operation is known as modulation. The question tests your understanding of modulation's role in the end-to-end chain. Given Data / Assumptions: We are discussing the transmitter function. The goal is to prepare digital information for transmission over an analog passband channel. Complementary receiver operation is demodulation (not asked here). Concept / Approach: Modulation maps discrete symbols to changes in a carrier: for example, ASK/QAM alter amplitude, FSK alters frequency among discrete tones, and PSK/QAM alter phase (and possibly amplitude). The net effect is to represent digital data as an analog waveform that fits the channel's frequency constraints and can propagate with acceptable signal-to-noise performance. By contrast, converting analog to digital is digitization (sampling/quantization), and echoing characters is a terminal feature unrelated to modulation. Step-by-Step Solution: Identify the need: map bits to a waveform that the passband channel can carry.Describe the act: alter carrier amplitude/frequency/phase per symbol mapping.Result: produce an analog signal whose parameters encode digital data.Choose “Converting digital signals to analog signals.” Verification / Alternative check: Practical systems (cellular, Wi-Fi, cable modems) use QAM/OFDM—explicit forms of modulation—demonstrating the conversion from digital payloads to analog RF waveforms at the transmitter. Why Other Options Are Wrong: Sending a file: application-layer function, not physical modulation. Converting analog to digital: this is digitization at the receiver (or ADC), not modulation. Echoing characters: terminal/line-diagnosis behavior, unrelated to modulation. None of the above: incorrect because option B is correct. Common Pitfalls: Confusing modulation with line coding; forgetting that demodulation is the inverse at the receiver; assuming all media are baseband and do not require a carrier (e.g., 10BASE-T is baseband, but many wide-area systems are passband). Final Answer: Converting digital signals to analog signals.

Question 14

Multiplexing methods: which technique places each input signal on a distinct carrier frequency so multiple signals share the same medium simultaneously?

Accepted Answer

Introduction / Context: Multiplexing allows several independent signals to share a single physical medium efficiently. Two foundational approaches are dividing by frequency (FDM) and dividing by time (TDM). This question checks whether you can correctly associate the technique that assigns different carrier frequencies to different signals so they can be transmitted at once without interference, given appropriate filtering and guard bands. Given Data / Assumptions: The medium supports a band of frequencies broad enough for multiple channels. Signals are isolated using filters and guard bands. We contrast frequency-division versus time-division approaches. Concept / Approach: In Frequency-Division Multiplexing (FDM), each input occupies a unique sub-band centered around its own carrier frequency. These sub-bands are summed and transported together. Receivers use tuned filters to recover the intended channel. By contrast, Time-Division Multiplexing (TDM) interleaves signals across time slots on a single carrier or baseband; synchronous TDM preassigns slots, while statistical/asynchronous TDM assigns slots dynamically based on demand. Thus, only FDM fits the description of shifting each signal to a different carrier frequency. Step-by-Step Solution: Identify keyword: different carrier frequencies per signal.Map to method: that is FDM.Differentiate from TDM: TDM separates by time, not frequency.Choose FDM as the correct answer. Verification / Alternative check: Broadcast radio and cable television are classical FDM systems; each station or channel occupies a specific frequency band. Telephone carrier systems historically used FDM before digital TDM came to dominate trunks. Why Other Options Are Wrong: Synchronous TDM: fixed time slots on one carrier; no per-channel carrier shifting. Asynchronous TDM: dynamic time slots; still time, not frequency separation. All of the above: false because only FDM uses different carriers. None of the above: incorrect because FDM is correct. Common Pitfalls: Mixing up FDM with FDMA (access method naming); assuming OFDM is TDM—Orthogonal FDM is still frequency-division at its core, though with orthogonal subcarriers. Final Answer: FDM.

Question 15

The convergence of microelectronics, computing, and communications has collectively given rise to which broad field that drives modern information systems and services?

Accepted Answer

Introduction / Context: Over recent decades, breakthroughs in microelectronics (integrated circuits), computing (hardware, operating systems, algorithms), and communications (wired, wireless, Internet) have converged. This synergy transformed how organizations operate and how individuals access, process, and share information. The umbrella term for this combined domain is widely used in academia, industry, and policy discussions. This question asks you to identify that field. Given Data / Assumptions: We are naming a broad, recognized discipline rather than a transient trend. The focus is on technology that enables information processing and communication. The term should encompass both computing and networking foundations built on microelectronics. Concept / Approach: The accepted collective term is Information Technology (IT). IT covers computing platforms, software, storage, networks, and the services built on top (cloud, data centers, cybersecurity). While the convergence created many downstream effects (business transformation, educational change), those are outcomes rather than the field’s name. “Information explosion” describes growth in data volumes, not the enabling discipline. Step-by-Step Solution: Identify the three pillars: microelectronics + computing + communications.Recall the common umbrella term spanning these: Information Technology.Eliminate outcomes and side effects (business/education changes, data explosion).Select “Information technology.” Verification / Alternative check: University departments, government strategies, and industry associations consistently use “Information Technology” to describe the combined domain driving digital systems and services worldwide. Why Other Options Are Wrong: Information explosion: a phenomenon, not the enabling field. Business revolution: consequence of IT adoption, not the field’s name. Educational upgradation: sectoral impact, not the domain label. None of the above: incorrect because IT is correct. Common Pitfalls: Confusing outcomes with disciplines; assuming “ICT” vs “IT” nuances matter here—either label covers the combined technologies, but “Information technology” matches the standard phrasing in such questions. Final Answer: Information technology.

Question 16

Workforce terminology: employees who spend much of their time away from the office but connect to company systems over telephone or data lines are commonly called what?

Accepted Answer

Introduction / Context: As remote work matured, organizations adopted terms to describe employees who work primarily outside traditional offices yet remain connected to corporate systems. Historically, dial-up lines, ISDN, and early broadband enabled such staff to access mainframes, file servers, and email from the field or home. This item asks for the standard term used to describe those workers who maintain connectivity while away from headquarters. Given Data / Assumptions: Connectivity occurs over public networks (telephone or data lines). Employees are frequently mobile or home-based. The term should be recognizable across decades of IT literature. Concept / Approach: The widely used term is telecommuters (also called teleworkers). It emphasizes the substitution of telecommunications for commuting to a central office. “Field workers” is a generic job-location descriptor but does not necessarily imply sustained remote system access. “Teleprocessors” is not a standard term for people; it more aptly describes devices or processes. “Company directors” is unrelated to the connectivity context. Step-by-Step Solution: Recognize the scenario: remote employees maintaining system access.Map to common terminology: telecommuters/teleworkers.Exclude generic or incorrect labels (field workers, teleprocessors, directors).Select “Telecommuters.” Verification / Alternative check: HR policies, labor studies, and IT user guides long refer to telecommuting programs; modern equivalents include remote/hybrid workers using VPNs and cloud services, still conceptually telecommuting. Why Other Options Are Wrong: Field workers: may be remote but not necessarily connected to systems continuously. Teleprocessors: not a personnel term. Company directors: unrelated to remote connectivity. None of the above: incorrect because “Telecommuters” fits precisely. Common Pitfalls: Assuming any offsite employee is a telecommuter; the defining feature is routine system access over networks, not merely working outside the office. Final Answer: Telecommuters.

Question 17

In classful IPv4 addressing, what is the default subnet mask associated with a Class B network block?

Accepted Answer

Introduction / Context: Although modern networks overwhelmingly use classless routing (CIDR), many exam questions still reference legacy classful IPv4 conventions. Under classful rules, each class (A, B, C) had a default subnet mask tied to its first-octet range. This question asks you to recall the default mask for a Class B network. Given Data / Assumptions: Class B first-octet range: 128–191 (with 127 reserved for loopback, not part of Class B). Default masks: Class A = 255.0.0.0, Class B = 255.255.0.0, Class C = 255.255.255.0. We are not considering VLSM/CIDR; this is strictly the historical default. Concept / Approach: Class B addresses use the first two octets for the network portion and the last two for hosts. The dotted-decimal mask that expresses “network = two octets, host = two octets” is 255.255.0.0. Options that either shorten the network portion (255.0.0.0) or lengthen it (255.255.255.0) correspond to Classes A and C, respectively, not Class B. Step-by-Step Solution: Recall classful defaults: A /8, B /16, C /24.Translate /16 to dotted decimal: 255.255.0.0.Match to the provided options and choose 255.255.0.0. Verification / Alternative check: Any elementary networking reference lists Class B's default as /16 (255.255.0.0). Subnetting exercises frequently start from this base mask before borrowing bits for subnets. Why Other Options Are Wrong: 127.0.01: malformed and also reflects the loopback class (127.x.x.x) rather than a subnet mask. 255.0.0.0: Class A default (/8). 255.255.255.0: Class C default (/24). None of the above: incorrect because 255.255.0.0 is correct. Common Pitfalls: Mixing up class ranges and masks; forgetting that 127.x.x.x is reserved and not a usable network class for addressing hosts. Final Answer: 255.255.0.0.

Question 18

In information systems and computer networking, what are typical uses of terminals at the edge of a system? Choose the most inclusive description that reflects how terminals interact with people and the underlying process.

Accepted Answer

Introduction / Context: Terminals are the human–machine interface points of an information system. In industrial control, retail point-of-sale, banking kiosks, or help-desk environments, terminals play multiple roles: gathering inputs, presenting outputs, and relaying decisions to the process or system being controlled. Given Data / Assumptions: “Terminal” refers broadly to an interactive end device (e.g., POS terminal, operator console, VT-style terminal, kiosk). Managers and operators use terminals both to view information and to enter commands. Terminals can be directly or indirectly connected to the physical process (through controllers or applications). Concept / Approach: A terminal’s function spans three directions: input (data capture), output (information display), and control (issuing actions). Good systems design recognizes that the same device often supports all three to close the decision loop: sense → decide → act, with humans in the loop as needed. Step-by-Step Solution: Identify terminal input role: entry of sensor readings, transactions, or form data.Identify terminal output role: dashboards, alerts, reports for managers/operators.Identify terminal control role: applying setpoints, approvals, or commands that alter the process.Since terminals routinely serve all three, select the inclusive choice. Verification / Alternative check: Consider a warehouse terminal: workers scan barcodes (input), supervisors view stock and KPIs (output), and managers authorize reorders or dispatches (control). The terminal thus participates in collection, communication, and action. Why Other Options Are Wrong: Collect only / Provide only / Communicate only: each is a partial view of a terminal’s capability; modern systems integrate all three. None of the above: Incorrect because terminals commonly support all listed roles. Common Pitfalls: Treating terminals as “display-only.” In practice, terminals are bi-directional endpoints in socio-technical workflows. Final Answer: All of the above

Question 19

In fiber-optic communications, the reduction of optical signal power as light propagates down the fiber is called what?

Accepted Answer

Introduction / Context: Optical links carry information as light through glass or plastic fibers. As light travels, some energy is lost due to absorption, scattering, and other mechanisms. The overall reduction in signal power per unit distance is a key design parameter because it dictates repeater/amplifier spacing and receiver sensitivity requirements. Given Data / Assumptions: The question asks for the general name of power loss in a fiber. We are not computing a value; we are identifying the correct term. Typical contributors include absorption, Rayleigh scattering, and macrobending/microbending losses. Concept / Approach: Total loss along the fiber is called attenuation, usually expressed in dB/km. While “scattering” names one physical cause of loss, the umbrella term that quantifies the outcome (power reduction from input to output) is attenuation. Step-by-Step Solution: Recognize we need the general effect, not a specific mechanism.Map “reduction in power with distance” to “attenuation.”Confirm that other terms either describe causes (scattering) or unrelated ideas (propagation simply means travel). Verification / Alternative check: Link budget calculations sum fiber attenuation (e.g., 0.2 dB/km at 1550 nm) with splice/connector losses to verify that received power stays above receiver sensitivity plus margin. Why Other Options Are Wrong: propagation: Not a loss term; it just means signal travel. scattering: A mechanism of loss, not the total measured reduction. interruption: Implies a break or outage, not gradual loss. None of the above: Incorrect because attenuation is the accepted term. Common Pitfalls: Confusing specific mechanisms (scattering) with the aggregate metric (attenuation), or mixing attenuation with dispersion (temporal spreading, not power loss). Final Answer: attenuation

Question 20

On a classic shared-medium Ethernet LAN using CSMA/CD (e.g., coaxial bus or hub-based half-duplex), how many pairs of stations can successfully communicate at the same time?

Accepted Answer

Introduction / Context: Ethernet has evolved from a shared collision domain (coax or hubs) to modern switched, full-duplex topologies. Understanding the legacy CSMA/CD behavior clarifies why collisions occur and why only one frame can occupy the medium at any given instant on a shared segment. Given Data / Assumptions: We are considering classic half-duplex, shared-medium Ethernet (single collision domain). All stations contend for the same channel using CSMA/CD. Question asks about simultaneous successful communication. Concept / Approach: In a single collision domain, if two transmit at once, a collision occurs and both must back off. Therefore, only one transmitter–receiver pair can be successfully exchanging a frame at a time. Switched, full-duplex Ethernet removes collisions and allows many simultaneous conversations, but that is a different topology than a shared medium. Step-by-Step Solution: Model the shared bus/hub as one channel.Apply CSMA/CD: simultaneous transmissions collide and are aborted.Conclude only one conversation can be in progress successfully at a time. Verification / Alternative check: Measurement on hub networks shows rising collision rates with load; bandwidth is shared and only one frame can be on the wire at once without collision. Why Other Options Are Wrong: 2 or 3 or multiple: Would require switches or separate collision domains. None of the above: Incorrect because “1” is correct for shared segments. Common Pitfalls: Confusing shared hubs with modern switches; switched Ethernet supports many simultaneous full-duplex links, but the question targets CSMA/CD on a shared medium. Final Answer: 1

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