A digital direct access arrangement (DAA) circuitry may be used to terminate the telephone connections at the user's end that provides a communication path for signals to and from the phone lines. Briefly described, the DAA provides a programmable means for the DC termination for a variety of international...http://www.google.ca/patents/US6201865?utm_source=gb-gplus-sharePatent US6201865 - Digital access arrangement circuitry and method for connecting to phone lines having a DC holding circuit with switchable time constants
