LEX
Local Exchange
LEC
Local Exchange Carrier
IXC
Interexchange Carrier
LATA
Local Access and Transport Area
PoP
Point of Present
PoI
Point of Interconnect
LATA 內由 LEC 經營
inter-LATA 由 IXC 經營
每一個 LATA 有一個 PoP 與 IXC 介接
uspstn.htm, Fri Mar 22 23:50:42 CST 2013
