Complex sentence: Calls can be placed from or received to the handset as if it were connected over-the-air directly to the GANC's point of presence, the system is essentially invisible to the network as a whole.
Split into simpler sentences: Calls can be placed from or received to the handset as if it were connected over-the-air directly to the GANC's point of presence. The system is essentially invisible to the network as a whole.