DESCRIPTION:
The SA9101 (Frame Alignment unit for PCM30 Systems) is a C-MOS device which implements the interface to PCM30 Transmission Systems.
In the receive direction, the device performs HDB3 decoding, Frame alignment (selectable between doubleframe and CRC-Multiframe) and extraction of signalling data.

FEATURES
■ Frame alignment/synthesis for PCM30 double frame and CRC-multiframe format.
■ Meets CCITT Rec.G704
■ Interface to route selectable between HDB3 and fibre optical
■ HDB3 outputs switchable between fully bauded and half bauded format
■ Error checking via CRC4 procedure
■ Insertion and extraction of alarms and facility signals
■ Selectable system - clock (4096 kHz/8192 kHz)
■ Selectable Interface mode (2048/4096 kBit/s) to system internal highway
■ Programmable offsets for receive and transmit data
■ Two frame receive buffer for receive route clock wander and jitter compensation
■ Slip detection and direction indication
■ Extended HDB3 error detection
■ Error counters for code errors (switchable to "Sizeros counter"), frame errors and CRC4 errors
■ Sub-multiframe assigned CRC Error indication with possibility of automatic insertion in Si-bit position of outgoing multiframe.
■ Simplified data transfer between SA9101 and controller, supported by data stacks for receive and transmit signalling data, selectable interrupt sources and DMA facilities.
■ Double frame marker for serial data extraction support
■ Repeated transmission of signalling data, if not updated.
■ Three transparent modes for timeslot 0 in transmit direction
■ Transparent mode for receive direction
■ HDB3 error indication
■ Idle channel data insertion selectable for any timeslot
■ Channel loopback capabilities, test and diagnostic capabilities
■ Parity checks