Identifies the telephone number of the customer employee, office, or agent that should be contacted on design/engineering matters.
USAGE: This field is conditional.
NOTE 1: Required on all DLRs in response to an ASR, otherwise optional.
DATA CHARACTERISTICS: 17 numeric characters (including 3 preprinted hyphens)
EXAMPLE: 2 1 2 - 3 3 4 - 1 2 3 4 - 6 7 8 9