DAA
Data Access Arrangement: A special interface for connecting modem ICs to a telephone line. CML has available, for free download, several DAA designs for its wireline telecom modems.
One of the functions of a DAA circuit is to provide a safety isolation-barrier between the phone line and the low voltage circuits that users' can touch.
Both data and and control information must be transferred successfully across the isolation barrier.
The electrical chracteristics that the DAA presents to the line are subject to various regulatory requirements.
The DAA must be relatively immune to such environmental stresses such as lightening and common-mode noise.