TelephonyCall dial(DOMString number); // Returns a object in "dialing" state
attribute boolean muted; // Should these live on the call/group?
attribute boolean speakerOnspeakerEnabled;
attribute any active; // Active call, for now. Could be a group in the future.
void startTone(DOMString tone);
void stopTone();
void sendTones(DOMString tones,
[optional] unsigned long toneDuration,
[optional] unsigned long intervalDuration);
attribute Function onincoming;