Introduction

The Advanced CMOS Frame Aligner PEB 2035 (ACFA) is a monolithic CMOS device which implements the interface to primary rate PCM carriers. It may be programmed to operate in 24- channel (T1) and 32-channel (CEPT) carrier systems.

特性 Features

Serial Interface to Line Interface Unit

● Frame alignment/synthesis for 2048 kbit/s (CEPT,

PCM 30) and 1544 kbit/s (T1, PCM 24)

● Meets newest CCITT Rec’s (Blue Book), FTZ Rec’s and

AT&T technical advisories (DMI, August 1986)

● Programmable formats for

PCM 30: Doubleframe, CRC Multiframe

PCM 24: 4-Frame Multiframe (F4), 12-Frame Multiframe

(F12, D3/4), Extended Superframe (ESF), Remote Switch

Mode (F72)

● Selectable conditions for loss of sync

● Selectable line codes (HDB3, B8ZS, AMI with ZCS)

● Unipolar NRZ for interfacing fibre optical transmission

routes

● Error checking via CRC4 or CRC6 procedures

● Insertion and extraction of alarms and facility signaling

● IDLE code insertion for selectable channels

Serial Interface to System Internal Highway

● System clock frequency of either 4096 kHz or 8192 kHz

● Selectable 2048/4096 kbit/s system internal highway with programmable receive/transmit shifts

● Two-frame deep elastic receive memory for receive route clock wander and jitter compensation

(can be reduced to one-frame length for PCM 30 master-slave applications)

● One frame elastic transmit memory (PCM 24 mode only) for transmit route clock wander and

jitter compensation

● Two different time-slot assignment procedures in PCM 24 mode

● Support for different signaling schemes

● Channel loop back capabilities

● Channel parity error monitoring

● Clear channel capabilities in PCM 24 mode

Microprocessor Interface

● Parallel, demultiplexed microprocessor interface for random access to control and status

registers

● Alarm interrupt capabilities

● Access to different signaling information:

– Sa-, E, Si -bits (register)

– Sa-bits (5-byte stack)

– FDL bits with the possibility of mixed insertion

– CCS, CAS-CC (common channel), CAS-BR (bit robbing) via 2/3-byte stacks with DMA/

interrupt support

● Extensive test and diagnostic capabilities

General

● Advanced CMOS technology

● Low power consumption (< 100 mW)

● Packaging: P-DIP-40, P-LCC-44