Identifies the fourth related unique PON that authorized the issuance of the related Access Service Request.
NOTE 1: May be used for relating a second cross-connected Access Service Request.
USAGE: This field is conditional.
NOTE 1: Required when DS3 is interoffice and both ends are crossed-connected, otherwise optional.
DATA CHARACTERISTICS: 16 alpha/numeric characters
EXAMPLE: 8 2 4 Z 9