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.

I am working with a Texas Instruments RF430 NFC tag, which is compliant with: ISO/IEC 14443-4 (ISO-DEP) NFC Forum Type 4 Tag NFC-B protocol NDEF-formatted storage I’m using an iPhone 12 running iOS 18, and my app uses the Core NFC framework. Using NFCNDEFReaderSessionDelegate, I am able to successfully read the first NDEF message from the tag. However, the tag stores multiple NDEF messages, and I would like to access the others. Based on the tag’s specification, these messages are accessible via an NDEF file located at file ID 0xE104. To try and access this additional NDEF file, I attempted to use NFCTagReaderSession with the NFCTagReaderSessionDelegate, intending to issue APDU commands. However, the tagReaderSession(_:didDetect:) delegate method is never called, even though the tag is present and detected using NFCNDEFReaderSession. My questions: Does Core NFC on iOS 18 support issuing custom APDU commands to ISO 14443-4 (NFC-B) tags like the TI RF430? Is the use of NFCTagReaderSession with NFC-B fully supported for tags that implement ISO-DEP (even if they are NDEF-formatted)? Is there any known limitation or configuration required to ensure tagReaderSession(_:didDetect:) is triggered for NFC-B/ISO-DEP tags?