Hi there,
I feel a little stupid 
Couldn’t understand from the manual how to take my keyboard sustain pedal and use it to start recording on my Ribbons.
I got into the cv mapping menu and now I just want the pedal to turn on and off recording.
What do I need to do?
Just a heads up, standard keyboard sustain pedals are not directly compatible with the CV/EXP input jack.
If you want footswitch-style control, you can use an expression pedal by rocking it back and forth, make a custom cable for a Yamaha FC5, or build a custom footswitch box. All of that is documented here: external footswitch for ribbons
CV, as the name suggests (Control Voltage) is an active source of voltage. A passive sustain pedal does not supply any voltage. So for the avoidance of further confusion, CV is not applicable in this specific case.
In addition to what Jaak described, if you don’t feel comfortable with DIY, or you don’t have a normally closed sustain pedal at hand (although most sustain pedals will have a so called polarity switch, which is just that: flipping a pedal from NO to NC and back), another way (and maybe more convenient) would be to use a MIDI controller to trigger variouos Ribbons functions.
Ok so maybe I will try to build one.
I understand my error now! I didn’t think about the touch as the record button… in my head I kept thinking I use the bypass button for recording.
Thanks so much!