Hello,
I am developing a cross-platform mobile app that communicates with an external accessory over a serial (UART) link.
HARDWARE : The accessory is an optical reading probe that connects to the phone via USB. Inside the cable there is a standard FTDI USB-to-serial chip (similar to common FTDI/CP210x USB-serial adapters).
WHAT WORKS On Android, our app:
Detects the USB device Opens the serial port Reads and writes raw bytes successfully
This wired FTDI path is fully implemented and working.
WHAT DOES NOT WORK On iPhone, using the same wired FTDI USB accessory:
We connect via Lightning or USB-C adapter The app never sees the FTDI device We cannot find a public iOS API to open a generic USB-serial port
MY QUESTION :
Is there any supported way for a third-party iOS app to communicate with a generic FTDI USB-serial device over a wired USB connection?
Specifically, am I missing:
A public Apple framework for USB serial? An Info.plist key or entitlement? A system driver on iOS similar to macOS AppleUSBFTDI (TN2315)?
Or is wired USB-serial on iPhone only possible with MFi-certified accessories (External Accessory framework) or another transport such as Bluetooth LE?
WHAT I HAVE ALREADY CHECKED
External Accessory: seems to require MFi hardware and a registered protocol string. Our FTDI probe is not MFi. TN2315 (AppleUSBFTDI): appears to be macOS only, not iOS. Physical USB connection: cable fits, but no serial API is exposed to the app.
ENVIRONMENT
Platform: iOS (iPhone) Language: C# / .NET-iOS Need: transparent byte-level serial read/write
SUMMARY:
Android USB-serial works with our FTDI wired accessory. iOS does not.
Am I missing something on iOS, or is generic FTDI USB-serial simply not supported for third-party iPhone apps?
Thank you for any guidance.
