This read-create Integer32 is a bit map of DS0s used by the endpoint, where each bit set to 1 represents a DS0 assigned to that endpoint, with the bit position corresponding to the DS0 number, and per the description this value cannot be changed once the row is active. An admin uses this to precisely define which timeslots on a DS1 line belong to a given endpoint, which matters for multi-channel (nx64) endpoints spanning several DS0s. Because it's locked after activation, an admin needing to add or remove a DS0 from an endpoint's channel set must delete and recreate the endpoint row.