Assam ASSEB HS Skill Telecom key terms

The loss of signal strength as it travels along a cable or through the air, usually measured in decibels per unit length. Higher attenuation means the signal must be boosted or regenerated sooner.

A logarithmic unit used to express ratios of power or signal level. In telecom work it describes gain, loss, and signal strength, so a 3 dB loss means roughly half the power remains.

The ratio between the strength of a wanted signal and the background noise at the same point. A higher ratio means clearer reception and fewer transmission errors.

The proportion of transmitted bits that arrive incorrectly, expressed as a fraction such as one error in a million bits. It is a standard measure of link quality.

The process of varying a carrier wave's amplitude, frequency, or phase to carry information. It lets low-frequency data travel efficiently over radio and cable channels.

A modulation scheme that combines amplitude and phase changes to pack several bits into one symbol. Higher-order QAM carries more data but needs a cleaner channel.

Combining several separate signals into one shared channel so they can travel together, then separating them at the far end. Common forms include time division and wavelength division.

Copper cable in which pairs of insulated conductors are twisted together to reduce interference. It is the standard medium for telephone lines and LAN cabling such as Cat 5e and Cat 6.

Unwanted transfer of signal energy from one cable pair or channel into a neighbouring one. It degrades quality and is reduced by tighter twists, shielding, and proper separation of cables.

Crosstalk measured at the same end of a link where the signal is injected. It is a key pass or fail measurement when certifying copper data cabling.

Copper cabling graded by performance, such as Cat 5e, Cat 6, or Cat 6A. The category sets the supported frequency and data rate, so the grade must match the installed service.

The total attenuation a fibre link may have while still delivering usable power to the receiver. It is calculated from transmitter power, receiver sensitivity, and splice and connector losses.

The small signal loss caused by joining two optical fibres, either by fusion or mechanical splicing. Each splice adds to the link's total loss and must stay within budget.

Joining two optical fibres by melting their ends together with an electric arc. It gives the lowest loss and strongest joint, and is standard for outside-plant and long-haul links.

A test instrument that sends light pulses into a fibre and analyses the returning reflections. It locates breaks, splices, and connector losses along the length of a link.

Carrying several independent signals on different wavelengths of light through one fibre at the same time. Dense WDM greatly increases the capacity of existing fibre routes.

A fibre access architecture where one feeder fibre is split by passive optical splitters to serve many subscribers. It is widely used for FTTH broadband because no powered equipment sits in the field.

The customer-side device in a fibre access network that converts optical signals into electrical service for the premises. It terminates the fibre and provides ports for phone, internet, and TV.

A technique that reserves a dedicated path between two parties for the whole call. Resources stay allocated even during silence, which suits voice but wastes capacity for bursty data.

Sending data as individually addressed packets that share network links and are reassembled at the destination. It uses capacity efficiently and underpins modern data networks and the internet.

A numeric label assigned to a device on an IP network so packets can be routed to it. IPv4 uses 32-bit addresses and IPv6 uses 128-bit addresses.

A number that shows which part of an IP address identifies the network and which part identifies the host. It lets devices decide whether a destination is local or must be sent to a router.

The router address a device sends traffic to when the destination lies outside its own subnet. A wrong or missing gateway is a common cause of no-internet complaints.

A logical grouping of switch ports that behaves like a separate network even when devices share the same physical switches. It improves security and reduces broadcast traffic.

The traditional circuit-switched telephone network that carries voice calls over copper and fibre trunks. It is gradually being replaced by IP-based voice services in many countries.

Carrying voice calls as data packets over an IP network instead of a dedicated voice circuit. It lowers cost but depends on good latency, jitter, and packet loss performance.

Variation in the delay between arriving packets. High jitter makes voice sound choppy or robotic even when overall bandwidth is sufficient.

The time a signal or packet takes to travel from sender to receiver. Excessive latency makes conversations feel delayed and slows interactive applications.

The process of transferring an active mobile connection from one cell or base station to another as the user moves. A successful handover keeps the call or data session uninterrupted.

The radio equipment and antennas at a cell site that connect mobile handsets to the network. It handles transmission, reception, and radio resource control for its coverage area.

Dividing a cell site's coverage into several directional sectors using separate antennas. It increases capacity and reduces interference by reusing frequencies more tightly.

Invisible energy radiated by electrical and radio equipment, including antennas and power wiring. Field strength falls quickly with distance, so exposure is managed through safe working distances.

The rate at which radio-frequency energy is absorbed by body tissue, usually quoted in watts per kilogram. Handset SAR limits are set by regulators to protect users from excessive exposure.

The minimum separation maintained from an antenna or radiating source so exposure stays within permitted limits. It is calculated from transmit power, antenna gain, and the applicable exposure standard.

A safety procedure in which an energy source is isolated, locked, and tagged before work begins. It prevents accidental energising of circuits or equipment while a technician is working.

Wearable safety gear such as helmets, gloves, goggles, and harnesses that reduce injury risk. Correct selection and inspection of PPE are mandatory before hazardous telecom tasks.

Connecting equipment or conductors to earth to provide a safe path for fault current and to stabilise voltages. Proper earthing protects people and equipment and reduces interference.

Devices and practices that divert sudden voltage spikes, such as lightning or switching transients, away from sensitive equipment. They are essential on outdoor lines and antenna feeders.

The boundary where the service provider's network ends and the customer's wiring begins. It defines who is responsible for faults, testing, and maintenance on each side.

Equipment located at the subscriber's site that connects the customer to the telecom service, such as routers, ONTs, and modems. Ownership and maintenance responsibility vary by contract.

A structured set of measurements, including continuity, length, attenuation, and crosstalk, that proves an installed cable link meets its category standard. Results are recorded and handed over as acceptance evidence.