100+ Free Telecom Professional Qualification Practice Questions

telecom-fundamentals-laws-ethics

Foundational communication theory, statutory laws, and professional regulations: PRC Telecommunications Regulations (中华人民共和国电信条例: telecom service classification, universal service obligations, interconnection rules, and network security mandates), PRC Cybersecurity Law (网络安全法), PRC Data Security Law (数据安全法), telecom network architecture (user plane, control plane, management plane), Nyquist sampling theorem (fs ≥ 2 fmax, band-limiting and anti-aliasing filters), Pulse Code Modulation (PCM uniform quantization vs non-uniform logarithmic quantization, A-law 13-segment compression in China/Europe with A=87.6 vs μ-law 15-segment compression with μ=255, 64 kbps standard voice channel bit rate 8 kHz × 8 bits), digital modulation techniques (BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, constellation mapping, bit error rate vs SNR, spectral efficiency in bps/Hz), Orthogonal Frequency Division Multiplexing (OFDM subcarrier orthogonality, IFFT/FFT modulation, cyclic prefix CP to eliminate ISI/ICI), multiplexing schemes (TDM, FDM, WDM, CDM, synchronous vs asynchronous multiplexing), and telecommunications professional ethical standards.

optical-transmission-access-networks

Optical fiber transmission systems, transport hierarchies, and broadband access architectures: Synchronous Digital Hierarchy per ITU-T G.707 (STM-1: 9 rows × 270 columns = 2430 bytes, 125 μs frame duration, 155.520 Mbps line rate; STM-4: 622.080 Mbps; STM-16: 2488.320 Mbps; STM-64: 9953.280 Mbps; RSOH, MSOH, AU-4 pointer, VC-4 container mapping), Optical Transport Network per ITU-T G.709 (OTN layered architecture: OPUk, ODUk, OTUk line rates OTU1 2.5G, OTU2 10G, OTU3 40G, OTU4 100G, OTUCn, Forward Error Correction Reed-Solomon RS(255,239), multi-layer tandem connection monitoring TCM), Dense Wavelength Division Multiplexing per ITU-T G.694.1 (DWDM 50 GHz / 100 GHz grid, C-band 1530-1565 nm / L-band 1565-1625 nm, Optical Add-Drop Multiplexer OADM, Reconfigurable OADM using Wavelength Selective Switch WSS), Passive Optical Networks (EPON IEEE 802.3ah 1.25 Gbps symmetric, GPON ITU-T G.984 2.488 Gbps downstream / 1.244 Gbps upstream, XG-PON ITU-T G.987 10G/2.5G asymmetric, XGS-PON ITU-T G.9807 10G/10G symmetric, wavelength plans 1490nm downstream / 1310nm upstream / 1550nm CATV, optical splitters 1:32 insertion loss ~15-17 dB, 1:64 insertion loss ~18-20 dB, Dynamic Bandwidth Allocation DBA, ranging mechanism), single-mode optical fiber characteristics per ITU-T (G.652 standard SMF zero-dispersion at 1310 nm, attenuation ~0.2 dB/km at 1550 nm; G.655 non-zero dispersion shifted fiber NZDSF; G.657 bend-insensitive fiber for FTTH; Rayleigh scattering, chromatic dispersion, polarization mode dispersion PMD), and optical link power budget calculations (Pt - Pr ≥ α*L + Σαc + Σαs + M).

wireless-mobile-communications

5G New Radio (NR), cellular system architecture, radio wave propagation, and mobile network engineering: 5G NR Radio Access Network (gNodeB architecture, CU-DU split per 3GPP Option 2 / Option 7-2x), 5G Core Network (5GC) Service-Based Architecture (SBA: AMF Access and Mobility Management, SMF Session Management, UPF User Plane Function, UDM Unified Data Management, AUSF Authentication Server, NRF Network Repository, PCF Policy Control, HTTP/2 RESTful service interfaces), 5G deployment options (Option 3x NSA with LTE eNodeB master anchor and EPC vs Option 2 SA pure 5GC/gNodeB), Massive MIMO (64T64R, 32T32R, multi-user MIMO, 3D adaptive digital/analog hybrid beamforming, CSI-RS channel state estimation), 5G network slicing (S-NSSAI = SST Slice/Service Type + SD Slice Differentiator for eMBB, URLLC, mMTC), 5G NR numerology and frame structure (Sub-6 GHz FR1 410-7125 MHz with μ=0/1/2 corresponding to 15/30/60 kHz subcarrier spacing; mmWave FR2 24.25-52.6 GHz with μ=2/3 corresponding to 60/120 kHz subcarrier spacing, 10 ms radio frame, 1 ms subframe, 14 OFDM symbols per slot), radio propagation path loss models (free space path loss, Okumura-Hata model, COST-231 Hata model, log-normal shadow fading, Rayleigh and Rician fast fading, Doppler frequency shift fd = v/λ * cos θ), link budget calculations (EIRP, receiver sensitivity, thermal noise floor N = -174 dBm/Hz + 10*log10(B) + NF), mobility management and handover measurement events (Event A1 serving above threshold, Event A2 serving below threshold, Event A3 neighbor offset better than serving for intra-frequency handover, Event A5, Event B1/B2 inter-RAT handover), and Carrier Aggregation (CA Primary Cell PCell, Secondary Cell SCell, Dual Connectivity EN-DC).

ip-routing-switching-networks

IP packet switching, routing protocols, modern transport architectures, and network softwarization: TCP/IP protocol suite vs OSI 7-layer model (TCP three-way handshake, four-way termination, sliding window, congestion control Slow Start / Congestion Avoidance / Fast Retransmit / Fast Recovery, UDP, MTU 1500 bytes, MSS 1460 bytes), IPv4 Variable Length Subnet Masking (VLSM), CIDR route aggregation, usable host address calculations (2^h - 2), private address ranges per RFC 1918 (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), IPv6 addressing architecture (128-bit address representation, Global Unicast 2000::/3, Link-Local fe80::/10, Unique Local fc00::/7, Multicast ff00::/8, Stateless Address Autoconfiguration SLAAC, Neighbor Discovery Protocol NDP Router Solicitation/Advertisement and Neighbor Solicitation/Advertisement replacing ARP), dynamic routing protocols (OSPF Link-State protocol, Dijkstra SPF algorithm, Area 0 backbone, LSA Types 1 Router, 2 Network, 3 Summary, 4 ASBR Summary, 5 AS-External, DR/BDR election; IS-IS Link-State protocol Level-1/Level-2; BGP-4 Path-Vector protocol, Autonomous Systems, AS-Path loop prevention, NEXT_HOP, LOCAL_PREF, MED multi-exit discriminator, BGP route decision order), Multi-Protocol Label Switching (MPLS 32-bit shim header: 20-bit Label, 3-bit Traffic Class Exp, 1-bit S bottom-of-stack, 8-bit TTL, Label Edge Router LER, Label Switch Router LSR, Label Distribution Protocol LDP, MP-BGP EVPN for data center interconnect), Segment Routing (SR-MPLS, SRv6 Segment Routing over IPv6 dataplane, Segment Routing Header SRH, Node SID, Adjacency SID, Binding SID), Software-Defined Networking (SDN control plane and data plane separation, OpenFlow protocol flow tables, Southbound and Northbound APIs), Network Functions Virtualization (NFV architectural framework: VNF Virtualized Network Functions, NFVI infrastructure, MANO Management and Orchestration comprising NFV Orchestrator, VNF Manager, and VIM Virtualized Infrastructure Manager), and IP Multimedia Subsystem / SIP signaling (RFC 3261 Session Initiation Protocol, P-CSCF Proxy, I-CSCF Interrogating, S-CSCF Serving, Home Subscriber Server HSS, Session Description Protocol SDP offer/answer model, VoLTE and VoNR voice session establishment).

telecom-power-environmental-systems

Telecommunications power infrastructure, battery energy storage, environmental cooling, and grounding safety: Telecommunications -48V DC power supply architecture (fundamental reason for positive terminal grounding: positive earthing minimizes electrochemical galvanic corrosion of underground copper conductors and telecom cables), nominal operating voltage range (-40V to -57V, float charge voltage -53.5V to -54.0V, boost/equalize charge voltage -56.4V), high-frequency switch-mode rectifiers (AC/DC conversion topologies, Power Factor Correction PFC cos φ > 0.99, N+1 active parallel redundancy, power conversion efficiency > 96%), telecom energy storage systems (Valve-Regulated Lead-Acid VRLA AGM/GEL batteries and Lithium Iron Phosphate LiFePO4 batteries, discharge depth DoD, battery backup capacity design formula C = (K * I * T) / (η * [1 + α * (t - 25)]) where K is safety margin 1.25, I is discharge load current, T is backup duration, η is discharge capacity coefficient, α is temperature coefficient 0.006/°C for lead-acid, and t is ambient temperature), Uninterruptible Power Supply (UPS online double-conversion architecture: Rectifier -> DC Link -> Inverter, static automatic bypass switch, zero transfer time, harmonic distortion THD < 3%), precision air conditioning (Computer Room Air Conditioning CRAC / CRAH, high Sensible Heat Ratio SHR > 0.90, precision environmental envelope temperature 23 ± 2°C and relative humidity 40% - 70%, hot/cold aisle containment), data center energy efficiency metrics (Power Usage Effectiveness PUE = Ptotal / PIT, MIIT green data center mandates PUE ≤ 1.30 for existing and ≤ 1.25 for new national computing hubs), and telecommunications lightning protection and joint grounding systems (Joint Grounding System 联合接地系统 combining AC ground, DC power ground, lightning ground, and protective ground onto a common grounding grid, grounding resistance requirement R ≤ 1.0 Ω per YD/T 5098 / GB 50689, equipotential bonding rings, and Surge Protective Devices SPD Class I/II/III).