Re: How does incoming caller ID work - and more specifically - can caller ID source data be controlled?

On 01/06/2020 05:39, Arlen Holder wrote:
> Tough question... likely only for Android freeware experts...
> 
> How does incoming "Calling Number Identification" work and more specifically
> is there a method you know of to CONTROL its source data?
> 
> Essentially, the goal is to shift incoming CallerID off of the
> system internal default contacts sqlite database onto a
> given privacy-oriented contacts database of your own choosing.
> 
This is part of the relevant telephony standards, this is a basic how it 
does it on GSM, ignoring ACKs and errors and stuff.

Tower sends a RING packet.
Tower sends a (possibly empty) "Calling Number Identification" packet.
Tower sends RING packets until:
    - answered - tower sends and receives voice packets
    - re-directed - tower sends and receives voice packets
    - cancelled - call is disconnected
    - times out - call is disconnected
Etcetera.

That's it.  To get a look at the "Calling Number Identification" packet 
you have to look inside the "call" application.

The actual layout of a "Calling Number Identification" packet is beyond 
the scope of this newsfroup, a deep-dive into the source of the Android 
"call" application would be required.

	Cheers,
		Gary	B-)

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