Which two parts of the transportation information transmission system is the most important

Transmission system, public service telephone system.

1, special transmission system is the core of the urban rail transit information communication system, it is responsible for a variety of applications to provide access. The main business of the rail transit system package live: language, data and images, different services on the system's bandwidth, delay, reliability and so on, which requires the transmission system has enough flexibility and reliability to ensure the successful completion of various services, services can be divided into different types: station - center business and neighboring station business two.

2, urban rail transit information communication system business telephone subsystem, is an important communication tool for rail transit operation and control, business telephone system according to the size of the rail transit has a different capacity, a station is basically a 2 mbit path (30 phones).