Progress indicator információs elem

The purpose of the Progress indicator information element is to describe an event which has occurred during the life of a call. The information element may occur two times in a message.

               8  7  6  5  4  3  2  1
        1      0  0  0  1  1  1  1  0 = 0x1E
        2            length  max 2+2
        3   1 ext b  b  0  a  a  a  a
        4   1 ext d  d  d  d  d  d  d

a)  Location (octet 3)
        Bits
        4  3  2  1
        0  0  0  0      User
        0  0  0  1      Private network serving the local user
        0  0  1  0      Public network serving the local user
        0  0  1  1      Transit network (Note 2)
        0  1  0  0      Public network serving the remote user
        0  1  0  1      Private network serving the remote user
        1  0  1  0      Network beyond the interworking point
        All other values are reserved.
        NOTE 2 - This value may be generated by some networks.
        NOTE 3 - Depending on the location of the users, the local public network and remote public network may be the same network.

b) Coding standard (octet 3)
        Bits
        7  6
        0  0            CCITT standardized coding, as described below
        0  1            ISO/IEC standard (Note 1)
        1  0            National standard (Note 1)
        1  1            Standard specific to identified location (Note 1)
        NOTE 1 - These other coding standards should be used only when the desired progress indication can not be represented with the CCITT-standardized coding.

c) Progress description (octet 4)
        Bits
        7  6  5  4  3  2  1                No.
        0  0  0  0  0  0  1  1.     Call is not end-to-end ISDN; further call progress information may be available in-band
        0  0  0  0  0  1  0  2.     Destination address is non ISDN
        0  0  0  0  0  1  1  3.     Origination address is non ISDN
        0  0  0  0  1  0  0  4.     Call has returned to the ISDN
        0  0  0  0  1  0  1  5.     Interworking has occurred and has resulted in a telecommunication service change (Note 5)
        0  0  0  1  0  0  0  8.     In-band information or an appropriate pattern is now available.
        All other values are reserved.
        NOTE 4 - The use of different progress descriptions is further explained in Annex G.
        NOTE 5 - This progress description value shall be used only in the case of interworking in a full ISDN environment, e.g. when bearer capability selection is not supported or when resource or route of the preferred capability is not available. In c
interworking with a non-ISDN environment a progress description No. 1 shall be used. If the destination address is non-ISDN, the progress description No. 2 shall be used.