Identifies the logical connection address between the provider’s switch and the related circuit.
USAGE: This field is conditional.
NOTE 1: Required when the BSC field on the EUSA or Transport Form is “F”, the VCACT field is “C”, “D” or “R” and the VST field is not populated.
NOTE 2: Required when the VST field is “B” and the VCACT field is “C” or “R”.
NOTE 3: Prohibited when the VST field is “A” or “C”.
NOTE 4: Prohibited when the BSC field on the EUSA or Transport Form is “C” and VST field is not populated.
NOTE 5: Otherwise optional.
DATA CHARACTERISTICS: 4 numeric characters
EXAMPLE: 1 7
NOTE 1: This example illustrates a numeric value but is left justified since it is treated as text.