That's not true. The midi works just fine. I just tested it with my ipad.

Yes, via USB you can use midi, e.g. with an iConnectMidi4 interface, which should also work without iPad connected.

Precisely..

And there is more solutions for this, which are under €80

It is.
I was referring to midi in out to hook up ( one straight midi out cable)to modules without additional externals.Not USB midi. (Meaning ; to use weighted keys to control hardware modules).

OK, it‘s more complicated now. I prefer traditional midi sockets, too. But all manufacturers have dropped them for their low-priced product lines.
At least you have the alternatives mentioned. In our church we have a DGX 630 from 2008, which only has a USB connection that is not yet suitable for iPad nor any of the current USB/midi interfaces, you really can do nothing with modules in that case. Now we finally replaced it with a P-255.

It also need a external power supply for the converter if you want to control external modules.



Again we are not talking about Midi to USB. We are talking about keyboards with USB out to physical Midi connector.

Your typical Midi to USB ( computer) will not work due to lack of power supply.

https://www.sweetwater.com/store/detail/MIDIExpand--keith-mcmillen-instruments-midi-expander?mrkgcl=28&mrkgadid=3301332467&rkg_id=0&product_id=MIDIExpand&campaigntype=shopping&campaign=aaShopping%20-%20SKU%20-%20Studio%20%26%20Recording&adgroup=Studio%20Mixers%20%26%20Control%20Surfaces%20-%20Keith%20McMillen%20Instruments%20-%20midiexpand&placement=google&adpos=1o2&creative=280136033989&device=m&matchtype=&network=g&gclid=EAIaIQobChMIhYHexJr84wIVGNtkCh0JZABGEAQYAiABEgJg_fD_BwE





Way more cables.

For home/ studio , no issues.

But for live, unless you are totally satisfied with onboard sounds (or iPad sounds if you are using ipad’s Soft synth via camera connection kit), not ideal.

Ipad here is only to manage onboard sounds of P121/125.

https://m.youtube.com/watch?v=neXswJJcatc


https://m.youtube.com/watch?v=gTu6soq2j_k




https://m.youtube.com/watch?v=FZbaHLz2wsY

The Keith McMillen Instruments MIDI Expander works only for the Softstep and some other devices by Keith McMillen. The description on Sweetwater is wrong. I use USB MIDI converters by this company based in Spain. https://compasflamenco.com/midi-c-3/

After reading this post, I went to GC to try the P-121. I enjoyed it enough to play 90 minutes on it. Didn't like the P-45 sitting right next to it. Liked the 115 last year and not so much the 125. Personal preferences. The 121 might be right for me with the 73 keys and the inviting price. But I really need to hear it on the battlefield (battlefield being any place that's NOT the small "keyboard korner" that lives in most Guitar Centers.

What‘s different between P115 and P125 at all? Both have the new version of the „Pure CF engine“ for the piano sound.
The P45 has an inferior piano sound generation.

“The main Concert Grand Piano tone on the P-125 uses 4-layer sampling as opposed to 3 layers found on the P115. The layer has been added to make the sound more dynamic and allows for a smoother transition between the samples.”

“10 new instrument sounds”

https://www.pianodreamers.com/yamaha-p125-review/