1.5 meter 22AWG DB9 Female Connector RS232 Serial RXD TXD GND Port to 3-pin Terminals Exapansion Cable MIDI DIN 3P - AliExpress
SGI Octane/O2 Midi Adapter from Epromfoundry, Inc. on Tindie
GitHub - cyberboy666/_transcribe_: midi to rs232 bridge - for performance control of old video mixers and switchers
Amazon.com: DecaBox MIDI to RS232 Bidirectional Converter : Musical Instruments
MIDI / RS-232 Converter
FT232RL USB TO MINI DIN 8P MD8 ADAPTER RS232 SERIAL CABLE FOR KORG X5(D) MIDI MUSIC SYNTHESIZER TO HOST PORT AG-001 FOR PC (FT232RL CHIP) Cable length:3m - Newegg.com