The term

transmission system refers to a system equipment that provides language, data, and image information transmission channels for various specialized communication subsystems and other specialties. The official telephone system is a system equipment for general official communication and communication between internal users and public telephone network users. The specialized telephone system is a specialized telephone equipment set up for control center dispatchers, station and vehicle base duty personnel to command, operate, manage, and ensure train safety, including dispatch telephones, inter station train telephones, station through telephones, and trackside telephones. The wireless communication system is a system equipment that provides wireless communication means between mobile personnel in operation and management departments, as well as between mobile personnel and fixed personnel. The video monitoring system image monitoring systcm provides video information related to train operation, substation equipment, disaster prevention, disaster relief, and passenger flow status for control center dispatchers, station duty officers, train drivers, etc. 2.1.6 Broadcasting system is a sound equipment used by control center dispatchers and station duty officers to notify passengers of train operation, safety, guidance, disaster prevention and other service information, and to issue work orders and notifications to staff. The Passenger Information System (PIS) is a system that relies on multimedia technology, computer technology as the core, and uses stations and on-board display terminals as media to provide information services to passengers