INSA: EfPdCtl" — “Insertion Effect A: Effect Pedal Control” (comes from the “VCM Pedal Wah” Effect Type.

"INSA: EfSpCt1" — “Insertion Effect A: Effect Speed Control”

The “INSA” refers to the Insertion Effect, the next abbreviation is the specific edit parameter - which can vary depending on the currently assigned Effect. The Data List Booklet and the Synthesizer Parameter Manual can be helpful here.

The Data List booklet (pdf) will give the full names of all the Effect Parameters
The Synthesizer Parameter Manual (pdf) will give you the definitions of all the parameters.

Please Download the following pdf manuals from the Yamaha.com corporate product page:
Data List Booklet
and the:
MX49/MX61/MX88 Synthesizer Parameter Manual

Thanks for your kind reply, but I am looking for a complete list of abbreviations that is not present in the documents you have indicated. Where can I find that "EfPdCt" means "Effect Pedal Control" of the effect type "VCM Pedal Wah"? For example?

Okay Orazio,
The way to use the manuals and learn the instrument is to NOT do it like you learn in class... where they teach you, separated from application. There you memorize away from actually using the item.
You want to learn your synth a little at a time, by going in context... that means... you are only seeing “EfPdCtl” because you are looking at an Insertion Effect parameter... probably in the Voice “Control Set”

First, look up the Insertion Effect, then review the parameter Name in the Data List booklet.
If you don’t know what the parameter does, then use the Synth Parameter Manual for details.

Say you were looking to apply the “VCM Pedal Wah” Effect to a Part or say you recalled a Part and discovered that one of the Control Assign setups had a Destination = “InsA: EfPdCtl".

Okay so what does that mean?
This is when you would break out the Data List booklet pdf... on the cover look for “Effect Parameter List” - page 33
Look through the Effect Types; find “”VCM Pedal Wah” - page 38
Listed are the full titles of the parameters that can manipulated.

Hopefully you have a Yamaha FC7 Pedal so that you can complete your learning exploration... it is the “Pd” (pedal)... probably controlling the Wah-Wah on an electric guitar or Clavinet sound.

... I think this means you'll have to sort out how the shortened names match the parameters inside the documentation through inference.

Ok. I started to make this matching by using the manuals and exploring the MX, yes i have both FC7 and FC3A. Thank you for the advices, now I understand how I have to work.. 🙂

If you run into any that are trouble, just post back here.