This attribute is an extension of the Closed User Group (CUG)
facility. If this attribute is set to a value of allowed, it specifies that
outgoing calls (from the DTE to the network) to the open (non-
CUG) part of the network are permitted. It also permits outgoing
calls to interfaces that have Incoming Access capabilities. If set to a
value of disallowed, then such calls cannot be made using this Dna
(the calls will be cleared by the local DCE).
This attribute corresponds to the ITU-T 'Closed User Group with
Outgoing Access' feature.