GENERAL DESCRIPTION
The D6571E chip is a digital speech/signal processing subsystem that implements all functions of TRUESPEECH® speech compression and voice prompts, telephone line signal processing, flash memory management and True FULL Duplex SpeakerPhone™ for an all digital answering machine. The D6571E is fully controlled by the system HOST through a simple interface protocol. The HOST processor provides activation and control of all system functions such as speech recording and playback, DTMF and call progress tone detection, DTMF and tone generation, and voice  rompting.

FEATURES
·  Superior quality TRUE SPEECH® Triple Rate Coder™ allowing selectable 11, 15 or 25 minutes of recording time per each 4 Mbit Flash Memory
·  PCM Recording
·  Flexible storage of incoming messages (ICM), outgoing messages (OGM). Supports multiple OGMs and multiple mailboxes.
·  TRUESPEECH®, natural -sound voice prompting, for Day/Time stamp and voice instructions
·  FLEXISPEECH™ variable speed, natural sound playback (50%  - 200%)
·  DTMF generation and detection with near-end echo cancellation for superior performance
·  Extended DTMF detection (A, B, C, D)
·  Automatic Gain Control
·  True FULL Duplex SpeakerPhone™ with both acoustical and near-end echo cancellation
·  Caller ID and Call Waiting CID demodulation (both Bell 202 and V.23)
·  FSK modem for CID and  a-5 support
·  Supports 4 Mb or 16 Mb Flash Memory Devices
·  Supports Time Stamp (message tag) modification
·  Programmable DTMF, CPT, VOX, CAS, and FSK Detectors Sensitivity
·  Digital Volume Control
·  µ-law and A-law codec support, selectable Master and Slave mode, selectable sampling rate.
·  General Purpose (CID) and Non-Erasable Storages