Android dtmf_tone_when_dialing

Sending DTMF tones over the uplink in-call

I'm working on a project that requires my app to be able to send DTMF tones on the voice's uplink frequency during an active call.

My 2 conditions are:

• We don't use a customized Android platform
• We don't need to root the phone

I've spent several days doing my homework and am aware that in-call DTMF sending is not supported by the current SDK/standard APIs. However, by using the relevant classes in com.android.internal.telephony I am hoping to mimic how the native Phone app does this. I followed this site on how to use internal APIs for standard 3rd party apps .

I've also set myself up with the Android OS dev environment and am able to run the Phone app in debug mode on an emulator to figure its inner workings.

I tried various ways on a stock standard emulator but the errors I got were:

After trying to install a renamed app based on Phone.apk's source using the sharedUserId of android.uid.phone, I got:

Installation error: INSTALL_FAILED_SHARED_USER_INCOMPATIBLE

No doubt due to the fact I don't have the system cert to sign it.

After trying to write a custom app based on the relevant DTMF tone sending code from Phone.apk's source, I get the following error at setting up the PhoneFactory;

java.lang.SecurityException: Permission Denial: not allowed to send broadcast android.provider.Telephony.SPN_STRINGS_UPDATED.

No doubt due to the fact my app doesn't have the right permissions, although AndroidManifest.xml is setup with the same permissions as Phone.apk.

I'm at a loss as to what else I could try. Does anyone have any suggestions?

Thanks in advance, Simon.