Roland System Exclusive packet Generator/Runner.
Hex bytes may be separated by spaces, commas, periods, or other punctuation.

About and instructions

From your friends at Splunge.foo.

This page builds Roland format System Exclusive messages (DT1 data set and RQ1 data request), then optionally sends them over Web MIDI and shows any DT1 replies.

  • Generate Sysex Text fills the Result area from the form. You can copy hex lines without a MIDI device.
  • Run Sysex sends each packet to the selected MIDI output and listens on the selected input until all requested bytes arrive or the reply wait expires.
  • Hex values must stay in Roland’s 7-bit data range (00–7F per byte). Model ID, start address, address step, and (for RQ1) bytes-to-request all use the same number of bytes (3 to 5); that width comes from the start address you enter. Paired hex/decimal fields update each other as you type.
  • Web MIDI requires a secure context (HTTPS or http://localhost) and browser permission including SysEx. MIDI port choices are stored in this browser only, not in shared links.
  • Copy Link To Clipboard saves the whole form (except MIDI ports) into the page URL. Open that link later to restore the same settings.
  • Increase Reply wait (ms) if the device answers slowly; each request waits until that much time has passed since the last reply packet unless the requested byte count arrives first.
Start Address
# Requests
Address Direction
Change Address By
Message Type
Bytes to Request

Web MIDI

MIDI is not connected yet.