Yeah, I think you are correct rwenzori - that's the x25 stuff. Dedicated leased lines. Come to think of it, not much has changed... as they say... you can take telkom out of the post office but you can't take the post office out of telkom!
SAPO Net is the X.25 Point to Point network. It is mostly used by the banks for EFT and interbank transfers. It is a legancy network that is in a bit of dis-repair.