Inventors:
Timothy J. Dupuis - Austin TX
Bradley J. Fluke - Austin TX
Jeffrey W. Scott - Austin TX
Navdeep S. Sooch - Austin TX
David R. Welland - Austin TX
Assignee:
Silicon Laboratories, Inc. - Austin TX
International Classification:
H04M 100
US Classification:
37939901, 379 9305, 379 9001, 379 9329, 37937602, 37939902, 37941301
Abstract:
Ring-detect interface circuit is disclosed for digital DAA circuitry to provide a plurality of selectable signals, including a ring monitor signal, on a ring-detect output pin. The interface circuitry allows the digital DAA circuitry to interface with advanced controllers, such as advanced DSPs, while still being compatible with older controllers that expect only a ring monitor signal on the ring-detect pin. The interface circuitry may include a multiplexer that receives multiple status bits or signals, including the ring monitor signal, and that has its output controlled by a multiple-bit control register. In addition, the ring monitor signal may be communicated as a digital signal across an isolation barrier from phone line side circuitry to powered side circuitry and ultimately made available on the ring-detect output pin. Corresponding methods for improving compatibility of digital DAA circuitry through the ring-detect interface circuit are also disclosed.
