Automatic baud rate detection
（重定向自Autobaud）
Automatic baud rate detection (ABR, autobaud) refers to the process by which a receiving device (such as a modem) determines the speed, code level, and stop bits of incoming data by examining the first character, usually a preselected sign-on character (syncword). ABR allows the receiving device to accept data from a variety of transmitting devices operating at different speeds without needing to establish data rates in advance.