The Called party subaddress IE

The purpose of the Called party subaddress IE is to identify the subaddress of the called party of the call. The network does not interpret this information. For the definition of subaddress see Rec. I.330.


               8  7  6  5  4  3  2  1
        1      0  1  1  0  1  1  0  1 = 0x71
        2            length  max 23
        3   1 ext b  b  b  a  0  0  0
        4      subaddress information

Subaddress information (octets 4, etc.)

        The NSAP X.213/ISO8348AD2 address, shall be formatted as specified by octet 4 which contains the Authority and Format Identifier (AFI). The encoding is made according to the "preferred binary encoding" as defined in CCITT Rec. X.213/ISO 8348 AD2 e
hen used for Terminal selection at the S interface (see Note 3). For the definition of this type of subaddress, see Recommendation I.334.

        For user specified subaddress, this field is encoded according to the user specification, subject to a maximum length of 20 octets. When interworking with X.25 [5] networks BCD coding should be applied.
        NOTE 2 - It is recommended that users apply the NSAP subaddress type since this subaddress type allows the use of decimal, binary and IA5 syntaxes in a standardized manner.

        NOTE 3 - It is recommended that users apply the Local IDI format (the AFI field coded 50 in BCD) when the subaddress is used for terminal selection purposes at the S interface. In this case the IA5 character syntax using only digits 0 to 9 shall b
for the DSP. Each character is then encoded in one octet according to Recommendation T.50/ISO 646, with zero parity in the most significant position.