该文档讲解了红外解码的原理，仅适用于入门级学习，不可用于非法行为-This document covers the infrared decoding principle applies only to entry-level learning, not for unlawful acts

一篇讨论红外解码的文档，特别是说明了空调控制码的实现方式与解码机制，比如upd6121.-An article in describing the decoding method of infrared control codes. The most interesting part is about to fully describe the implementation method of HVAC control codes such as upd6121