Both sizes of the new iPad Pro have lost the Lightning as well as the 3.5mm audio port. But now there is USB-C.
This is the first time Apple has used an industry standard for mobile devices. Unfortunately, the audio port that the MacBook Air has retained is no longer included.
So if you want to use wired headphones on your iPad, you can use the small USB-C to headphone connector adapter for nine dollars. Or you can buy headphones that have a USB-C connector.
Disadvantageous if you want to use one and the same sound converter on the new iPad Pro, MacBook and iPhone: You will need at least two adapters, one from Lightning to 3.5mm and one from USB-C to 3.5mm. The MacBook has retained the audio interface. In addition to the purchase of a Bluetooth model, a headset with a conventional 3.5mm plug is the best option.
With all other combinations there may also be adapters, but not always for all combinations and also not in all directions.
