Telecommunication Fundamentals Quiz

Communication Systems

• Short distance communication utilizes infrared (IR) signaling.
• Long distance signaling requires robust transmission circuits.
• Six data circuits function within railway station areas, serving telecom safety needs.
• Loop resistance affects transmission loss in quad cable pairs; maintaining low resistance is crucial.

Cable Jointing Techniques

• Jointing methods include straight, through/derivation, transformer, condenser, and loading coil joints.
• Thermo shrinkable jointing kits are specified for various cable sizes according to RDSO standards.
• Underground quad cables must comply with RDSO specifications RDSO/SPN/TC/57/2006.

Telecommunication Equipment

• Termination of cables is done using Krone or Wago type modules.
• 10 Pair/20 Pair connection termination is exclusive to Indian Railways for their telecom applications.

Mandatory Tests Before Commissioning

• Conduction tests must show 56 ohms/loop km.
• Insulation resistance should exceed 10 M Ohms.
• Transmission loss testing involves connecting loudspeakers in parallel to ensure even sound distribution.

Public Address System (PA System)

• Conference systems feature various units (chairman, secretary, delegate) connected through a central amplifier.
• A priority switch on the chairman unit mutes delegate microphones during speeches.
• Speaker phasing ensures multiple loudspeakers operate in unison to avoid feedback issues.

Uninterruptible Power Supply (UPS)

• UPS systems should provide at least 6 KVA backup power for one hour at full load in an N+1 configuration.

Integrated Security System (ISS)

• ISS incorporates under vehicle scanners, baggage scanners, and CCTV for comprehensive security management.

Passenger Information System

• Call center services cover accommodation status, reservation inquiries, train schedules, and fare information.
• Clocks at stations may be analog, digital, or GPS-based to provide accurate timekeeping.

Earthling and Surge Protection

• Surges can result in significant equipment damage, accounting for 27.4% of total electrical losses.
• Common causes of surges include lightning, equipment switching, and circuit breaker tripping.
• Lightning produces extreme heat (30,000 K) and high voltage (10 million volts).

Earth Resistance Characteristics

• Ideal earth electrodes are low resistance, corrosion-resistant, robust, and made from low carbon steel.
• Earth resistance can be affected by soil composition, temperature, and moisture content.

Reducing Earth Resistance

• Techniques to reduce earth resistance include using a mixture of salt, charcoal, and sand.
• Compliance with maintenance-free earth practices is essential, requiring routine checks every three years.
• Employing a ring grounding system allows for parallel connections to decrease resistance pathways.

Test your knowledge on various telecommunications concepts including short and long distance signaling, data circuits used in railway stations, and loop resistance. This quiz covers essential criteria for jointing and transmission losses in quad pairs. Perfect for students and professionals in the telecommunications field.