GENERAL DESCRIPTION
The DS21Q58 E1 quad transceiver contains all the necessary functions for connecting to four E1 lines. The DS21Q58 is a direct replacement for the DS21Q50, with the addition of signaling access and improved interrupt handling. It is composed of a line interface unit (LIU), framer, and a TDM backplane interface, and is controlled through an 8-bit parallel port configured for Intel or Motorola bus operations or serial port operation.

FEATURES
Four Complete E1 (CEPT) PCM-30/ISDN-PRI Transceivers
Pin Compatible with the DS21Q50 and DS21Q59
Short-Haul Line Interfaces
32-Bit or 128-Bit Crystal-Less Jitter Attenuator
Frames to FAS, CAS, and CRC4 Formats
CAS/CCS Signaling Support
4MHz/8MHz/16MHz Clock Synthesizer
Flexible System Clock with Automatic Source  Switching on Loss-of-Clock Source
Two-Frame Elastic-Store Slip Buffer on the Receive Side
Interleaving PCM Bus Operation Up to 16.384MHz
Configurable Parallel and Serial Port Operation
Detects and Generates Remote and AIS Alarms
Fully Independent Transmit and Receive Functionality
Four Separate Loopback Functions
PRBS Generation/Detection/Error Counting
3.3V Low-Power CMOS
Large Counters for Bipolar and Code Violations, CRC4 Codeword Errors, FAS Word Errors, and E Bits
Eight Additional User-Configurable Output Pins
100-Pin (14mm x 14mm) LQFP Package

APPLICATIONS
DSLAMs
Routers
IMA and WAN Equipment