RBSE Sec Voc Telecom key terms

The relationship stating that current through a conductor equals voltage divided by resistance (I = V/R). It underpins every calculation of load, drop, and supply capacity in telecom power and equipment work.

Two ways of connecting components. In series, the same current flows through each part and resistances add; in parallel, the same voltage appears across each branch and conductances add. Used to design battery strings and distribution boards.

Two rules for circuit analysis: current into a node equals current out, and the sum of voltage changes around any closed loop is zero. They let technicians solve networks that simple series-parallel rules cannot handle.

A method that replaces any linear two-terminal network with an equivalent voltage source in series with a resistance. It simplifies fault analysis and matching of loads to sources in telecom equipment.

The rate at which electrical energy is transferred, measured in watts and equal to voltage times current in a DC circuit. Power budgeting determines battery backup, rectifier sizing, and heat load in telecom shelters.

The ratio of real power to apparent power in an AC circuit, ranging from 0 to 1. A low value means reactive current wastes capacity, which matters for rectifiers, UPS units, and site energy audits.

A device that converts alternating current into direct current, typically using diodes. Telecom sites use rectifier banks with float and boost charging modes to supply equipment and charge battery banks.

A stored-energy system, usually lead-acid or lithium-ion, that supplies DC power to telecom equipment when mains fails. Capacity is rated in ampere-hours and sized against load current and required autonomy hours.

Deliberate connection of equipment metalwork and circuit reference points to the ground to limit shock risk and provide a return path. Telecom sites use separate body, equipment, and lightning earth pits bonded together.

A modulation scheme in which the amplitude of a high-frequency carrier varies in step with the information signal while frequency and phase stay constant. It is simple but wastes power in the carrier and both sidebands.

A scheme in which the carrier's instantaneous frequency shifts in proportion to the modulating signal while amplitude remains constant. It resists amplitude noise well, which is why FM broadcast and many radio links use it.

A modulation method in which the phase of the carrier is varied according to the message signal. It is closely related to frequency modulation and forms the basis of many digital phase-shift keying schemes.

A number describing how strongly a carrier is modulated, such as the ratio of peak frequency deviation to modulating frequency in FM, or the peak amplitude ratio in AM. It predicts bandwidth and distortion.

Quadrature amplitude modulation combines two carriers in phase quadrature, each amplitude-modulated, so many bits travel per symbol. Higher orders such as 256-QAM raise throughput but need better signal-to-noise ratio.

The ratio of wanted signal power to noise power at a point in a system, usually expressed in decibels. It sets the achievable error rate and the highest modulation order a link can sustain.

The fraction of received bits that are wrong, typically written as a number like 10^-6. It is the standard quality measure for digital links and depends on signal-to-noise ratio and coding.

Adding redundant bits during transmission so the receiver can detect and correct errors without retransmission. It improves link margin and is standard in optical, wireless, and satellite systems.

An error-detecting code that treats data as a polynomial and appends a remainder calculated by division. The receiver recomputes it; a mismatch triggers discard or retransmission. Common in frames and packets.

A digital encoding process that samples an analog signal, quantises each sample to a level, and codes it as binary words. It underlies 64 kbit/s telephony channels in plesiochronous and modern transport networks.

Rounding a continuously varying sample to the nearest allowed discrete level during analog-to-digital conversion. The resulting rounding error is quantisation noise, reduced by using more bits per sample.

Sharing a transmission channel by allocating each user a repeating time slot. It underpins E1/T1 carriers and legacy digital hierarchies, where 32 channels of 64 kbit/s form one 2 Mbit/s E1.

A technique that reserves a dedicated end-to-end path for the whole duration of a call. It guarantees capacity and constant delay but wastes resources during silence, unlike packet switching.

A technique that breaks data into packets routed independently through shared network links. It suits bursty traffic and underpins IP networks, but needs congestion control and buffering to manage delay variation.

A seven-layer reference framework describing how network functions divide from physical transmission up to applications. Technicians use it to isolate faults, for example distinguishing a cabling fault from an addressing fault.

The practical four-layer protocol suite of the Internet: link, internet, transport, and application. IP handles addressing and routing while TCP adds reliable, ordered delivery over unreliable networks.

Assigning logical numeric addresses to interfaces so packets can be routed. IPv4 uses 32-bit addresses written in dotted decimal; IPv6 uses 128 bits. Subnet masks divide networks into usable ranges.

Dividing a larger IP network into smaller logical networks by borrowing bits from the host portion of the address. It improves address efficiency, limits broadcast domains, and supports structured addressing plans.

The process of choosing the path a packet takes across interconnected networks using routing tables built by static configuration or dynamic protocols. It differs from switching, which forwards within a local segment.

A thin glass or plastic strand that guides light by total internal reflection, carrying very high bandwidth with low loss and immunity to electrical interference. It consists of a core, cladding, and protective coating.

The complete reflection of light at a boundary when it strikes above the critical angle from a denser to a rarer medium. It is the mechanism that confines light inside an optical fibre core.

A measure of the light-gathering ability of a fibre, derived from core and cladding refractive indices. A larger value accepts light over a wider cone but increases modal dispersion in multimode fibre.

Loss of signal power as it travels along a medium, expressed in decibels per kilometre for fibre. It arises from absorption and scattering and determines how far a link can run before regeneration or amplification.

Sending several optical signals at different wavelengths through one fibre simultaneously using multiplexers. Dense WDM multiplies capacity without laying new cable, a core technique in backbone transport networks.

A logarithmic unit expressing the ratio of two powers, equal to ten times the base-10 logarithm of the ratio. Telecom uses it for gain, loss, and levels because large ranges compress into small convenient numbers.

The ratio of power radiated in a preferred direction to that of a reference antenna, usually expressed in dBi or dBd. Higher gain concentrates energy into a narrower beam, trading coverage angle for reach.

A plot of an antenna's radiated field strength against direction, showing main lobe, side lobes, and nulls. It guides tilt, azimuth alignment, and interference planning during site installation.

An elliptical region around the direct line-of-sight path between two antennas where obstructions cause signal loss. At least sixty percent clearance of the first zone is normally required for reliable microwave links.

An unobstructed straight path between transmitter and receiver, needed for high-frequency microwave and free-space optical links. Earth curvature, terrain, and buildings must be accounted for in path planning.

Variation in received signal caused by reflections arriving at different times and combining destructively. It is countered with diversity reception, equalisation, and adaptive modulation in microwave and mobile systems.

The process of transferring an active mobile connection from one cell or base station to another as the user moves. Smooth handover requires overlapping coverage and coordination between network elements.

Dividing a service area into small cells with reused frequencies at sufficient distance to limit interference. It allows high capacity with limited spectrum and is the foundation of all mobile networks.

Devices and practices that divert transient overvoltages from lightning or switching away from sensitive equipment. Telecom sites combine earth pits, surge arrestors, and proper bonding to protect radio and transmission gear.

Wearable safety gear such as helmets, gloves, safety shoes, harnesses, and eye protection. Telecom field work requires it for tower climbing, cable pulling, splicing, and work near live electrical circuits.

Any task performed where a fall could cause injury, including tower and mast work. It requires fall-arrest harnesses, anchor points, tool lanyards, and a permit-to-work system under Indian safety regulations.

The Telecom Regulatory Authority of India, a statutory body that regulates tariffs, interconnection, quality of service, and spectrum-related practice. It issues regulations and recommendations distinct from licensing, which is handled by the Department of Telecommunications.

The Indian government department responsible for telecom policy, licensing, spectrum assignment, and coordination of standards. It also oversees public sector operators and compliance with licence conditions.

An Indian licensing framework allowing one licence holder to offer multiple services such as voice, data, and long distance under a single authorisation with defined entry fees and rollout obligations.

A teaching approach in which the instructor performs a skill step by step while learners observe and then practise under supervision. It suits splicing, crimping, and meter use in telecom trade training.

Breaking an occupation into its component tasks and sub-skills to decide what to teach and in what order. It aligns vocational curricula with real job roles and underpins competency-based lesson planning.

Instruction organised around demonstrated workplace competencies rather than time spent in class. Learners progress when they meet performance criteria, which suits modular vocational qualifications and skill assessment.

Ongoing checks during learning, such as observation, quizzes, and practical exercises, used to guide teaching rather than to grade. It helps trainers correct technique before a final summative trade test.

Agreed procedures governing conduct in a training lab, covering electrical isolation, tool handling, eye protection, first aid, and emergency shutdown. They must be explained and enforced before any practical session begins.