What is the operating system of China Telecom Tianyi smartphone?

The only operating system for Tianyi smartphones is Installation, Installation! It’s mainstream! Those telecom non-smart phones are a BREW system based on JAVA, which can expand the functions of mobile phones through the Tianyi Space platform. (Wow, there are so few applications, and they are so expensive. Tianyi thought it was Apple. A game cost more than ten yuan. Later, I directly downloaded JAVA games and never patronized Tianyi Space again.)