W91031

The Winbond Caller Identification device W91031, is a low power CMOS integrated circuit used to receive physical layer signals transmitted according to Bellcore and British Telecom (BT) specifications. There are two types of Caller Identifications, the first type is on-hook calling with caller ID message and the second type is call on waiting. The W91031 device provides all the features and functions of the Caller Identification specification for both these types, including FSK demodulation, Tone Alert Signal detection and ring detection. The FSK demodulation function can demodulate Bell 202 and CCITT V.23 Frequency Shift Keying (FSK) with 1200 baud rate. The Tone Alert Signal detect function of W91031 can detect the dual tones of the Bellcore CPE* Tone Alerting Signal (CAS) and the BT idle State and Loop State Tone Alert Signal. The line reversal for BT, ring burst for CCA or ring signal for Bellcore can be detected by the ring detector.

There are two modes of FSK W91031 data output interface. The first mode is a data transfer activated by the device, whose clock and data change depending upon the changing frequency of the FSK analog signal input. The second mode allows a microcontroller to extract 8-bit data from the device serially; the device notifies the micro-controller when 8-bit data has been received.