Quad T1/E1/J1 Transceiver

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The DS21Q55 is a quad software-selectable T1, E1, or J1 MCM device for short-haul and long-haul applications. Each port is composed of a line interface unit (LIU), framer, HDLC controllers, and a TDM backplane interface, and is controlled by an 8-bit parallel port configured for Intel or Motorola bus operations. The DS21Q55 is software compatible with the DS2155 single-chip transceiver. It is pin compatible with the DS21Qx5y family of products.
DS21Q55, DS21Q55N: Block Diagram DS21Q55, DS21Q55N: Block Diagram Enlarge+

Key Features

  • Complete T1/DS1/ISDN-PRI/J1 Transceiver Functionality
  • Complete E1 (CEPT) PCM-30/ISDN-PRI Transceiver Functionality
  • Long-Haul and Short-Haul Line Interface for Clock/Data Recovery and Waveshaping
  • CMI Coder/Decoder for Optical I/F
  • Crystal-Less Jitter Attenuator
  • Fully Independent Transmit and Receive Functionality
  • Dual HDLC Controllers
  • 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 Connect to Asynchronous Backplanes Up to 16.384MHz
  • 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz Clock Output Synthesized to Recovered Network Clock


  • Channel Banks
  • Channel Service Units (CSUs)
  • Data Service Units (DSUs)
  • DSL Add/Drop Multiplexers
  • Muxes
  • Routers/Switches
  • Routers/Switches
  • T1/E1 Test Equipment
Request Reliability Report for: DS21Q55N 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

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.

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