Identifies the telephone number of the customer technical contact.
USAGE: This field is conditional.
NOTE 1: Required when the TECH CON (NPANXX) field is populated, otherwise prohibited.
DATA CHARACTERISTICS: 14 numeric characters (excluding 3 preprinted hyphens)
EXAMPLE: 7 0 3-5 5 5-1 4 8 4-2 2 6 4