Hello,
I am investigating call behaviour on a dual SIM iPhone.
Observed behavior:
- A specific line is selected in Settings > Cellular > Default Voice Line.
- Our app initiates the native call flow by opening a phone-number URL scheme with the destination number.
- The native Phone app does not always place the call using the selected default line.
Expected behaviour:
- The native Phone app should place the call using the line selected in Settings > Cellular > Default Voice Line
Questions:
- In this flow, is line selection fully controlled by iOS?
- Is there any supported way for an app to ensure the native Phone app respects the selected default line?
- Is this a known limitation or known issue on dual SIM devices?
Any clarification on expected iOS behaviour would be appreciated.