Telecommunications Cabling Quiz

Cables with two closely spaced conductors twisted together.

Unwanted electrical interference between signal pairs.

Reduces electrical interference in cables by twisting adjacent wires.

A protective layer to prevent high-frequency noise from interfering with signal transmission.

Used for indoor telephone connections.

Used for outdoor telephone installations.

Indicates the number of independent signal pairs within a cable.

The size of the individual wires within the cable.

Used for indoor wiring for telecommunications, equipment interconnections, and various systems.

The armoured cable is covered with a layer of polythene, meeting sheath specifications.

Specific colours are assigned to each wire pair within a 5-pair cable, in a defined way.

A colour scheme is used for 20 pairs using main colour and mate colour. Main/mate pairs arranged for specific wire pairs.

50 pair cable consists of 5 sets of 10 pairs.

100 pair cable consists of 5 sets of 20 pairs.

The primary colours used in the cable's colour coding system (Blue, Orange, Green, Brown, Grey).

Secondary colours used (White, Red, Black, Yellow) in conjunction with main colours

A group of two wires sharing a colour.

A method where an insulated conductor in an electrical field gains a potential difference relative to the ground due to its capacitance.

An alternating current in a conductor creates a magnetic field that induces an EMF (electromotive force) in nearby conductors.

Alternating current used in railway traction systems.

The overhead wire system that carries electrical power to trains.

Connecting a conductor to the Earth. This provides a path for current.

Unwanted voltage or current induced in electrical circuits due to nearby alternating current sources.

Additional frequencies within a current signal besides the fundamental frequency.

Electromotive force; a voltage that drives electric current.

Disruption of electrical signals from electromagnetic fields or other sources.

The insulating layer around a cable.

Extra cable length needed beyond the measured route, accounting for variations and connections.

Additional cable length required to account for ground elevation changes along the route.

Needed distance set aside when a cable path crosses railway tracks; a 2.5-meter buffer on each side is standard.

Cable crossing clearance for bridges: 10 meters for major bridges, 5 meters for minor bridges.

Required space for cable connections. 10 meters from both ends.

A buffer zone required for Local exchange (LC) gateways. 3 meters minimum is needed.

Space required around station buildings for cable installation, 10 meters for station /OFC (Optical Fiber Cable) hut.

Method for determining the total cable length required for one section (route length, allowances, etc.)

Cable placement in a large area (yards/stations) when many tapping points/locations are involved.

A cable type (6 Quad or higher) suitable for dense tapping point areas; high-capacity.

Maximum allowable voltage induced in telecommunication circuits due to power lines, categorized by normal/abnormal operation and short circuit conditions. Values are 60V, 150V, and 430V rms respectively.

Maximum current (15 milliamperes) allowed to flow due to electrostatic induction in telecom cables as per I.T.U.-T recommendations.

Maximum allowable voltage for interference to speech transmission in communication circuits, measured in millivolts.

Unwanted current and voltage induced onto telecom cables by strong electromagnetic fields created by railway power systems.

Unwanted electrical noise from electromagnetic fields that interferes with data signaling.

Specific type of noise measured using a psophometric meter that degrades analog voice communication.

Dividing communication circuits to prevent the buildup of induced voltages by using isolating transformers at set intervals, thus preventing problems.

Telecom cables should be shielded with aluminium sheath and steel tape to minimize interference in the magnetic field regions near railway tracks.

Telecom cables should be laid on the side opposite feeding posts, at least 1 meter from metallic OHE parts and substation ground equipment. This also applies to substation earthing.

Telecom cables should be placed in RCC pipes for 300 meters on each side of a feeding point.

RCC markers with "IR/6 QUAD CABLE" and a logo are required every 50 meters, at joints, and derivations.

SSE/JEs of Open Line and Concerned Organizations (e.g., Projects) must inspect cable laying after completion.

When telecom cables cross or run parallel to 11KV+ power cables, PTTC approval is needed. Maximize horizontal clearance, at least 0.6 meters.

Keep the length of parallelism as short as possible. If over 0.8 km, take appropriate safety measures.

Surge protection devices are advisable to protect telecom networks from induced voltage, aligning with PTTC guidelines.

Absence of sheath and armour continuity, and improper earthing near power cables can lead to AC induction issues.

The ratio of induced voltage in a conductor with a metallic sheath to the induced voltage without the sheath. It represents the reduction in induced voltage due to the presence of the sheath.

Voltage developed in a conductor due to electromagnetic fields from nearby sources, like a power line's magnetic field.

A metal covering around a cable that helps shield the internal conductors from external interference.

The reduction in induced voltage achieved by the electric current in a conductor (sheath) due to the magnetic field it creates

The voltage difference between the conductor core and the cable's sheath.

The voltage difference between the conductor core and the Earth.

Guidelines issued by the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) for permissible induced voltages, calculation methods, and protective measures to reduce interference.

A graph illustrating the effects of induced voltages on telecommunication cables due to AC traction, relevant for determining acceptable voltage levels for reliable communication.

Alternating current (AC) power at 25,000 volts and 50 cycles per second used for powering trains, a common source of induced voltage on telecommunication lines.

Induced voltage, leading to signal interference, and potential safety hazard for personnel and equipment if not mitigated. Cable length and screening factor directly affect the voltage.

Cable laid beneath the ground for running telecommunication circuits parallel to railway tracks, reducing induced voltage effects.

Electrical devices used to isolate communication circuits from induced voltages, limiting their impact on the circuit.

Maximum allowable voltage induced into telecommunication equipment to maintain signal integrity and personnel safety.

Ratio of induced voltage in a conductor with a metallic sheath to the voltage induced in the absence of a sheath.

Recommended voltage levels for telecom personnel and equipment: 60 V in normal operation, 150V with precautions and 430V during faults.

Underground cables are preferred for crossing tracks, minimizing exposure to induced voltages.

Cables used in long-distance communication networks in railway electrified areas, often incorporating paper and PVC insulated quads.

A type of telecom quad cable with a specific construction, often used for long-distance applications.

The diameter of the copper wire used in certain types of railway telecom cables.

The diameter of the copper wire used in other types of railway telecom cables for long distance applications.

Paper and PVC insulated quad cables, designed for long-distance telecom circuits in railway electrified areas.

Common cable type for long-distance voice and signalling circuits, replaced older cable systems due to bandwidth.

Optical Fiber Cable network that is now replacing older copper cable systems for long-distance voice and signaling.

A detailed description of the layering of materials in the cable (conductor, petroleum jelly, dummy tube, binder, polyester tape, etc.).

Plain annealed high conductivity copper wire used as the electrical conductor in the telecom cable.

A specific colour code for each conductor (A-Wire, B-Wire, C-Wire, D-Wire) within a 4-Quad polyethylene-insulated cable.

A specific colour code for each of the six conductors (A-Wire to F-Wire) in a 6-Quad cable, used for easy identification of the wires.

A pair of wires arranged diagonally opposite to each other, forming a signal pair in a quad cable.

A method for holding the conductors of a quad cable together using nylon yarn or coloured tape.

The theoretical resistance to current flow through a cable.

The diameter of individual wires within a PIJF 4/6 Quad Cable (0.9mm) which define how much current can be carried.

Telecommunication cables with four conductors arranged as a quad, used for various railway communication circuits.

The material used for the cable's core, typically copper.

A cable that transmits data using light signals, replacing traditional copper cables in many railway applications.

Solid polythene layer surrounding each conductor, providing electrical isolation.

A measure of the insulation's ability to resist current flow. Must be greater than 5000 mega ohms/km.

A configuration of a telecom cable with six separate conductor groups, often used alongside Optical Fiber Cable (OFC).

A type of telephone cable with conductors arranged in pairs, used for telecommunication.

Water resistant compound filling the cable core, enhancing insulation.

A type of telephone cable that contains conductors in groups of four (quads).

Helically wrapped tape, impregnated with jelly, over the core for additional protection.

Polythene-coated aluminium tape, applied longitudinally over the core, to stop moisture.

Electromagnetic interference resulting from electrical equipment on railways, affecting telecommunication cables.

Polythene layer surrounding the core and moisture barrier.

Voltage generated in a conductor by an external magnetic field.

A screen made of aluminium wires/strips to prevent electrical interference.

A protective metal layer covering a cable to reduce interference.

A tape wrapped over the aluminium screen, coated in a compound like barium chromate, to stop oxidation.

The reduction in induced voltage achieved by the electric current in a conductor (sheath), due to magnetic fields.

Extruded PVC sheath over the screen, providing additional protection and a grey color.

Galvanised steel tape wrapped in two layers over the intermediate sheath.

The outermost protective layer, usually black in color.