Indicator designating a circuit portion as the master leg/segment on a multipoint configuration.
NOTE 1: Designates a circuit portion contained within the LATA (from an end user location) as the master leg/segment.
NOTE 2: Only one leg/segment on a multipoint circuit can be designated as the master; however, any number of other legs/segments can be designated as an alternate to the master.
NOTE 3: Leg/segments designated as an alternate master will be designed with the same functionality as the master leg/segment.
NOTE 4: All multipoint circuit configurations must contain a designated master leg/segment.
VALID ENTRIES:
M = This is the master leg/segment.
A = This is an alternate to the master leg.
R = Remove this as the master or alternate master leg/segment.
NOTE 1: Valid entry of "M" is prohibited if the MST field on the Transport, EUSA or another MSL Form is "M".
USAGE: This field is conditional.
NOTE 1: Required when the LEGACT field is "N" and this leg/segment is the master/alternate master, otherwise optional.
DATA CHARACTERISTICS: 1 alpha character
EXAMPLE: M