If the keyboard does not appear on iPhone/iPad/iPod touch when KDC is connected in HID iOS mode, the user can press the DOWN button to toggle the onscreen keyboard. For the KDC400/470/475/480/485, it is the small button located on the left side of the KDC.
You can also use the iOS Keyboard option on the KDC, which enables the display of a soft keyboard after sending data to and iOS device in HID mode. Enabling this is required if using iOS OS version is 15.x or later.
Please try with "iOS Keyboard" enabled on the KDC.
KDC Menu -->BT Config-->iOS Keyboard, or scan the desired barcode below: