The NW6006 device is a single-chip, 3/5 Volt CMOS caller ID with call waiting detection circuit. It can receive signals following Bellcore GR-30-CORE & SR-TSV-002476, BT SIN227 & SIN242, and ETSI ETS 300 788-1/-2 specifications. The NW6006 provides 1200 baud Bell 202 and ITU-T V.23 FSK demodulation, detection in stutter dial tone mode and CAS/DT-AS detection. Two seperate differential input amplifiers allow the device to be connected with both Tip/Ring and Telephone Hybrid receive pair. FSK demodulation is implemented only on Tip/Ring, while DT-AS(or CAS) detection can be on either Tip/Ring or Hybrid Receive. In addition, NW6006 provides a serial FSK data interface via which the data can be selected to be processed as a bit stream or extracted from a 1 byte built-in buffer. An on-chip Stutter Dial Tone Detector is provided to support the voice mail applications. The device can be used in feature or cordless phones with voice mail for BT Calling Line Identity Presentation (CLIP), CCA CLIP and Bellcore Calling Identity Delivery (CID) systems. It can also be used in caller ID boxes, modem, fax machines, answering machines, database query systems and Computer Telephony Integration (CTI) systems.