Dear, Toofy!
DPC is the address for routing in SS7 network with particlar network indicator. It has a local significance. It is impossible to address a node in world -wide manner by means of DPC.
GT is use for Global addressing.
How GT translation is perfrmed and about Numbering Plan, Nature of Adress, Translation Type Indicator and the Subsystem Number – see ITU-T Q.714 (and also 711-713).
BR