Quad T1/E1/J1 Transceivers

Industry's First 4-Port Transceivers to Switch Among All T1, E1, and J1 Standards without External Component Changes

Please check latest availability status for a specific part variant.


The DS21455 and DS21458 are quad monolithic devices featuring independent transceivers that can be software configured for T1, E1, or J1 operation. Each is composed of a line interface unit (LIU), framer, HDLC controllers, and a TDM backplane interface, and is controlled via an 8-bit parallel port configured for Intel or Motorola bus operations. The DS21455* is a direct replacement for the older DS21Q55 quad MCM device. The DS21458, in a smaller package (17mm CSBGA) and featuring an improved controller interface, is software compatible with the older DS21Q55.

*The JTAG function on the DS21455/DS21458 is a single controller for all four transceivers, unlike the DS21Q55, which has a JTAG controller-per-transceiver architecture.
DS21455: Block Diagram DS21455: Block Diagram Enlarge+

Key Features

Four Independent Transceivers, Each Having the Following Features:
  • Complete T1 (DS1)/ISDN-PRI/J1 Transceiver Functionality
  • Complete E1 (CEPT) PCM-30/ISDN-PRI Transceiver Functionality
  • Short- and Long-Haul Line Interface for Clock/Data Recovery and Waveshaping
  • CMI Coder/Decoder
  • Crystal-Less Jitter Attenuator
  • Fully Independent Transmit and Receive Functionality
  • Dual HDLC Controllers
  • On-Chip Programmable BERT Generator and Detector
  • Internal Software-Selectable Receive- and Transmit-Side Termination Resistors for 75Ω/100Ω/120Ω T1 and E1 Interfaces
  • Dual Two-Frame Elastic-Store Slip Buffers that can Connect to Asynchronous Backplanes Up to 16.384MHz
  • 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz Clock Output Synthesized to Recovered Network Clock
  • Programmable Output Clocks for Fractional T1, E1, H0, and H12 Applications
  • Interleaving PCM Bus Operation
  • 8-Bit Parallel Control Port, Multiplexed or Nonmultiplexed, Intel or Motorola
  • IEEE 1149.1 JTAG-Boundary Scan
  • 3.3V Supply with 5V Tolerant Inputs and Outputs
  • DS21455 Directly Replaces DS21Q55
  • Signaling System 7 (SS7) Support
  • RAI-CI, AIS-CI Support


  • Channel Banks
  • Channel Service Units (CSUs)
  • Data Service Units (DSUs)
  • Muxes
  • Routers
  • Switches
  • T1/E1 Test Equipment

CAD Symbols and Footprints

  • DS21455N+
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >


    Related Resources

    Belle Isle 2020
    05/29/2020 - 05/31/2020, Detroit, MI
    2020 Detroit Grand Prix - Chevrolet Detroit Grand Prix presented by Lear Fast Facts The Chevrolet Detroit Grand Prix presented by Lear was hosted on Belle Isle, May 29 - 30 2020. The event featured the cars of the NTT IndyCar Series, the IMSA WeatherTech SportsCar Championship and the Trans Am Series presented by Pirelli. The weekend is collectively referred to as the Chevrolet Detroit Grand Prix presented by Lear and it once again featured the Chevrolet Dual in Detroit IndyCar doubleheader.