The Test Head needs to connect into the telephony circuit so it is important to understand Test Access and how a circuit can be routed to the test unit.
The diagram below shows two possible connection paths for a Digital Subscriber Line (DSL) enabled telephone line. The voice and broadband service can be provided by the main telecom company Incumbent Local Exchange Carrier (ILEC) or with Local Loop Unbundling (LLU) a third party Competitive Local Exchange Carrier (CLEC) may provide the broadband part. A third option where the 3rd party offer the voice and broadband is also available but not shown in this example.
To stop customers moving to other suppliers it is important to manage any faults on their line quickly and efficiently. If the serivce is provided by two parties it becomes even more critical to prove the fault ownership onto the right supplier.
To access the customers telephone line to test the copper path or to test the Digital Subscriber Line Access Multiplexer (DSLAM) it is necessary to fit a Test Access Switch Matrix (TASM) or Test Access Module (TAM) in the metallic path of the customers circuit.