sysex

SysEx, short for System Exclusive, is a category of MIDI messages used to transmit manufacturer- or device-specific data that falls outside standard channel messages. A SysEx message begins with the status byte 0xF0 and ends with 0xF7, with the payload carried in between as 7-bit data bytes. Because the content is defined by the sending device or manufacturer, SysEx can be lengthy and highly specialized, enabling tasks such as bulk parameter transfers, patch/data dumps, firmware updates, and configuration dumps.

Manufacturer IDs are used to route SysEx data to the correct device. After the start byte, the message includes a manufacturer ID: either a one-byte ID (0x01–0x7F) or a three-byte ID that starts with 0x00 followed by three bytes. The bytes that follow the ID are defined by the manufacturer and can represent any device-specific data or commands.

Universal SysEx is a standardized subset defined by the MIDI Manufacturers Association. These messages use a common header and are intended to be understood by multiple devices. They include both non-real-time and real-time variants, enabling identity queries, timing commands, and general data exchanges that are independent of a specific manufacturer. Real-time universal SysEx can be transmitted during performance, whereas non-real-time variants are typically used for configuration and management tasks.

Compatibility and considerations: SysEx is inherently vendor-specific, so interoperability between different manufacturers is limited. Large SysEx payloads may require segmentation over multiple MIDI packets, and some devices or interfaces may impose size or routing restrictions. Despite these limitations, SysEx remains a powerful mechanism for advanced configuration, data transfer, and firmware-related operations in MIDI-equipped systems.