MIDI Expression iO has 4 inputs, full size MIDI In / Out ports, and a 9V connector for standalone operation and costs $154 USD.
Out of stock. More units expected by November 2023.

https://www.audiofront.net/MIDIExpression.php

Thank you very much for mentioning the MIDI Expression iO. Just ordered one.

I think Midi Expression IO is just what I'm looking for.
Now I'm waiting for notification ...

Bonjour,
I'm looking for a USB MIDI interface for 4 expression pedals such as M-Audio EX-P or Yamaha FC-7 (to match with the 4 Organteq pedals).
What can you suggest ?

Merci !

MIDI Expression iO has 4 inputs, full size MIDI In / Out ports, and a 9V connector for standalone operation and costs $154 USD.
Out of stock. More units expected by November 2023.

https://www.audiofront.net/MIDIExpression.php

Bonjour,
I'm looking for a USB MIDI interface for 4 expression pedals such as M-Audio EX-P or Yamaha FC-7 (to match with the 4 Organteq pedals).
What can you suggest ?

Merci !

This product might help, although you would need 4 of them (one for each expression pedal), and 4 available USB ports on the computer or in a USB hub attached to the computer.

https://beatbars.com/en/expression-to-midi.html

Merci !