Unfortunately I think there’s no such docs.
Ask a questions. We’ll try to answer.
>like which GT defined for SMSC
someone unassigned E.164 from operator numbering. Preferable old numbering.
>which GT for LU
Auth triplets request to HLR – by E.214 of subscriber.
Auth responce – by E.164 of serving node.
>which GT for MT Call
for what?