Asterisk: The Future of Telephony

Name

CallingPres() — Changes the presentation for the Caller ID

Synopsis

    CallingPres(presentation)

Changes the presentation parameters for the Caller ID on a Q931 PRI connection. These parameters should be set before placing an outgoing call. The argument presentation controls two things: whether or not the person being called can view the Caller ID information (known as presentation), and whether or not the Caller ID information has been verified by an authoritative source (known as screening).

Tip

This application has been replaced by the SetCallerPres() application, which is easier to use and less dependent on the internal Zaptel structures.

This application takes the call presentation setting and the screening setting and combines them into one number. The values themselves are defined in the ITU Q931 standard, as shown in Tables B-1 and B-2.

Table B-1. Screening is controlled by bits 2 and 1

Bit 2	Bit 1	Explanation
0	0	Caller ID information was provided by the user, and not screened.
0	1	Caller ID information was provided by the user, and successfully verified.
1	0	Caller ID information was provided by the user, and verification failed.
1	1	Caller ID information was provided by the network.

Table B-2. Presentation is controlled by bits 7 and 6

Bit 7	Bit 6	Explanation
0	0	Presentation of the Caller ID information is allowed.
0	1	Presentation of the Caller ID information is restricted.
1	0	The number is not available due to interworking.
1	1	Reserved.

Bits 3, 4, 5, and 8 should all be set to zero (0). Please note ...