Am79C30A

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.

The Am79C30A/32A provides a 192-Kbit/s full duplex digital path over four wires between the TE located on the subscriber's premises and the NT or PABX linecard. All physical layer functions and procedures are implemented in accordance with CCITT Recommendation I.430, including framing, synchronization, maintenance, and multiple terminal contention. Both point-to-point and point-to-multipoint configurations are supported.

The Am79C30A/32A processes the ISDN basic rate bit stream, which consists of B1 (64 Kbit/s), B2 (64 Kbit/s), and D (16 Kbit/s) channels. The B channels are routed to and from different sections of the Am79C30A/32A under software control. The D channel is partially processed by the DSC/IDC circuit and is passed to the microprocessor for further processing.

The Main Audio Processor (MAP) uses Digital Signal Processing (DSP) to implement a high performance codec/filter function. The MAP interface supports a loudspeaker, an earpiece, and two separate audio inputs. Programmable on-chip gain is provided to simplify use of low output level microphones. The user may alter frequency response and gain of the MAP receive and transmit paths. Tone generators are included to implement ringing, call progress, and DTMF signals.

A Peripheral Port (PP) is provided to allow the B channels to be routed off-chip for processing by other peripherals.
This por t is configurable as either an industry-standard IOM-2 port, or as a serial bus port (SBP).

The TE design process is simplified by the availability of certified protocol software packages, which provide complete system solutions through OSI Layer 3.