AX.25 is a data link layer protocol used in amateur radio for packet radio communications. It is designed to facilitate the transmission of digital data over radio frequencies. AX.25 is based on the X.25 protocol and includes features such as:
- Packet Structure: AX.25 defines a specific format for packets, which includes fields for addressing, control, and data.
- Addressing: It supports multiple addressing schemes, allowing for point-to-point and point-to-multipoint communications. Each packet can include the call signs of the sender and receiver.
- Error Detection: AX.25 includes mechanisms for error detection and correction, ensuring reliable data transmission over potentially noisy radio channels.
- Digipeating: The protocol supports digipeating, which allows packets to be relayed through multiple stations to extend their range.
- Use in APRS: AX.25 is commonly used in Automatic Packet Reporting System (APRS) applications, which provide real-time information such as location data and messages.
AX.25 is widely used by amateur radio operators for various applications, including messaging, telemetry, and remote control.