iPhone - Incoming call problems on some networks
I have initiated debug of problems with some providers, where incoming calls are not working with iPhone. I am working closely with people working for a mobile provider. Some facts we found out until now:
- It looks like providers using Siemens GSM HW have problems
- Everything else works (data, outgoing calls, SMS)
- Error reported by cental at mobile provider is something about "Incorrect protocol error"
it looks like something is added by protocol conversation by iPhone that is not standard. It may be that Siemens equipment strictly follows standards and doesn't let through something "a bit different".
We are now trying to go a bit deeper and debug the problem on lower network level. It may be, that something can be changed by provider to let it work (something like - ignore non compliant protocol....) but I bet we'll see Apple patch soon since this is also happening to not-hacked roaming phones AFAIK.
I'll keep u updated. If somebody has more technical info, please share it with us.