The external call transfer – is the call transfer to a telephone line other than the company’s telephone line. The internal call transfer – the transfer of an incoming call to another addressee registered on the same telephone line.
Call
Origination is the collecting of the call started by a calling party on a PSTN,
and handing off the call to a VoIP endpoint or to other exchange phone company
for completion to a called party
Call
Termination is a handing off or routing of calls from one Telephone Company to
another.