I am attempting to communicate over serial with a USB-C device and an M-Series iPad. I have proven the device to communicate as expected (baud rate, parity, etc) via a Swift app on Mac using a third party library (IOKit) that utilizes the "AppleUSBACM (v5.0.0)" driver on macOS. I am looking to recreate this communication via iPadOS and a custom DriverKit driver that provides this same interface. There is not an example from Apple for serial communication and DriverKit but there is a couple for communicating from an app to the dext, and for other networking examples. There are also other mentions in WWDC videos but they are incomplete and do not provide the needed structure. Communicating between a driver extension and a client app Connecting a network driver Bring your driver to iPad with DriverKit System Extensions and DriverKit My question revolves around architecture and how to set up a driver for these needs. I have gotten the examples to run and understand what is needed for entitlements and other local signing needs. But what I don't understand is if you need a basic setup similar to the "Communicating between a driver extension and a client app" where your base driver subclasses IOService and has two arms. One that subclasses IOUserclient and allows communication between the dext and your Swift app. And another arm that subclasses IOUserSerial or IOUserUSBSerial. I assume then that these two share buffers of memory set up by the base class that allows communication between the two. I have had little luck getting IOUserUSBSerial to compile and have made more progress on IOUserSerial. But when running that and with the supposed idVendor plist entry I am not getting that part of the dext to start or recognize when the USB device is plugged in. Long story short, I'm looking for a basic architecture or example reference to explain serial communication in DriverKit. Devices: Custom USB-C hardware that is CDC ACM compliant iPad Air 5th gen with M1 chip (iPadOS 17.2) M1 MBP (macOS 14.2.1)