GENERAL DESCRIPTION
The Am79C30A Digital Subscriber Controller (DSC) Circuit and Am79C32A ISDN Data Controller (IDC) Circuit, shown in the Block Diagram, allow the realization of highly-integrated Terminal Equipment for the ISDN. The Am79C30A/32A is fully compatible with the CCITT-I-series recommendations for the S and T reference points, ensuring that the user of the device may design TEs which conform to the international standards.

DISTINCTIVE CHARACTERISTICS
■ Combines CCITT I.430 S/T-Interface Transceiver, D-Channel LAPD Processor, Audio
■ Processor (DSC device only), and IOM-2 Interface in a single chip
■ Special operating modes allow realization of CCITT I.430 power-compliant terminal equipment
■ S- or T-Interface Transceiver
   — Level 1 Physical Layer Controller
   — Supports point-to-point, short and extended passive bus configurations
   — Provides multiframe support
■ Certified protocol software support available
■ CMOS technology, TTL compatible
■ D-channel processing capability
   — Flag generation/detection
   — CRC generation/checking
   — Zero insertion/deletion
   — Four 2-byte address detectors
   — 32-byte receive and 16-byte transmit FIFOs
■ Audio processing capability (DSC circuit only)
   — Registers for implementation of software-based speaker phone algorithms
   — Dual audio inputs
   — Earpiece and loudspeaker drivers
   — Codec/filter with A/µ selection
   — Programmable gain and equalization filters
   — Programmable sidetone level
   — Programmable DTMF, single tone, progress tone, and ringer tone generation
   — Programmable on-chip microphone amplifier
■ Pin and software compatible with the Am79C32A ISDN Data Controller (IDC™) Circuit. The Am79C32A is used in data-only applications.