Among the following rail transit communication systems, which systems can our transmission and access products participate in? (Multiple Choice)

Question

Options

• APIS system
• BTransmission System
• CVehicle-to-ground wireless dump system
• DVideo surveillance system

• A
  13% (4)
• B
  80% (24)
• C
  7% (2)

Explanation

Transmission and access products form the physical and logical backbone of rail transit networks, so they directly participate in the Transmission System (B) - this is the core network infrastructure these products are specifically built for. They also directly support the Video Surveillance System (D), since CCTV requires transmission links and access equipment to carry video streams from cameras to control centers across the station/line network.

PIS (A) is incorrect because the Passenger Information System is an application-layer system - it sits on top of the network and uses dedicated display/audio endpoints and content servers; the transmission layer supports it, but PIS is not a system these products directly participate in as a communication subsystem. Vehicle-to-ground wireless dump (C) is incorrect because it relies on specialized high-speed wireless technology (e.g., WLAN hotspots or LTE) designed for bulk train-to-ground data offload - this is handled by dedicated wireless equipment, not standard transmission and access products.

Memory tip: Think "Build the road (B = Backbone) and watch the road (D = surveillance cameras)" - transmission products are the transmission system, and access products connect the video eyes watching it. PIS and wireless dump are specialized end applications/technologies that ride on or beside the network rather than being built from it.

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