* telephone exchange
* telephone switch
Both telephone exchange or telephone switch are a system of electronic components that connects telephone calls. This process was manually before, nowadays it is an automatically process.
* Inside Plant
Telecomunication equipments that located in the telecompany building, such as DSLAM. In CATV, possible called CMTS.
* Outside Plant
Telecomunication equipments that located between main distribution frame (MDF) and User End instrument (or called Customer Premises Equipment).