These appear to be the relevant patents: https://patents.google.com/patent/US6415439B1/en https://patents.google.com/patent/US6415439B1/en includes some aspect

These appear to be the relevant patents: https://patents.google.com/patent/US6415439B1/en https://patents.google.com/patent/US6415439B1/en includes some aspects of the MIDI protocol in the tables; does this cover the LPC information the SWEETPEA authors couldn't figure out? https://patents.google.com/patent/US6317714B1/en https://patents.google.com/patent/US6317714B1/en https://patents.google.com/patent/US6281939B1/en https://patents.google.com/patent/US6281939B1/en It doesn't look like anyone's published a reverse-engineering of the protocol. Where does one get a 49.86mhz(??) maker-level transmitter these days?