Description
The MH89790B is Mitel’s CEPT PCM 30 interface solution, designed to meet the latest CCITT standards PCM 30 format with CRC-4. The MH89790B provides a complete interface between a 2.048 Mbit/sec digital trunk and Mitel’s Serial Telecom Bus, the ST-BUS.
The MH89790B is a pin-compatible enhancement of the MH89790, permitting the removal of the tuneable inductor and inclusion of the external NAND gate used for generating RxD.

FEATUREs
• Complete primary rate 2048 kbit/s CEPT transceiver with CRC-4 option
• Selectable HDB3 or AMI line code
• Two frame elastic buffer with 32µs jitter buffer
• Tx and Rx frame and multiframe synchroniza-tion signals
• Frame alignment and CRC error counters
• Insertion and detection of A, B, C, D signalling bits with optional debounce
• Line driver and receiver
• Per channel, overall, and remote loop around
• Digital phase detector between E1 line and ST-BUS
• ST-BUS compatible
• Pin compatible with the MH89790
• Inductorless clock recovery
• Loss of Signal (LOS) indication
• Available in standard, narrow and surface mount formats
• Supports single supply rail operation

APPLICATIONs
• Primary rate ISDN network nodes
• Multiplexing equipment
• Private network: PBX to PBX links