3.3V E1/T1/J1 Quad Line Interface

3.3V E1/T1/J1 Quad Line Interface Unit for Short-Haul and Long-Haul Applications
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Status Explanations for product status codes

Part Number Status
DS21448 Active: In Production. See Ordering Information for details.


The DS21448 is a quad-port E1 or T1 line interface unit (LIU) for short-haul and long-haul applications. It incorporates four independent transmitters and four independent receivers in a single 144-pin PBGA or 128-pin LQFP package. The transmit drivers generate the necessary G.703 E1 waveshapes in 75Ω or 120Ω applications and the DSX-1 or CSU line build-outs of 0dB, -7.5dB, -15dB, and -22.5dB for T1 applications.

Data Sheet

Download this datasheet in PDF formatDownload Rev 3 (PDF, 836kB)
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Errata DS21448 21448A1.pdf
An evaluation board is available: DS21448DK

Key Features

  • Four Complete E1, T1, or J1 LIUs
  • Supports Long- and Short-Haul Trunks
  • Internal Software-Selectable Receive-Side Termination for 75Ω/100Ω/120Ω
  • 3.3V Power Supply
  • 32-Bit or 128-Bit Crystal-Less Jitter Attenuator Requires Only a 2.048MHz Master Clock for E1 and T1, with the Option to Use 1.544MHz for T1
  • Generates the Appropriate Line Build-Outs With and Without Return Loss for E1, and DSX-1 and CSU Line Build-Outs for T1
  • AMI, HDB3, and B8ZS Encoding/Decoding
  • 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz Clock Output Synthesized to Recovered Clock
  • Programmable Monitor Mode for Receiver
  • Loopbacks and PRBS Pattern Generation/ Detection with Output for Received Errors
  • Generates/Detects In-Band Loop Codes, 1 to 16 Bits, Including CSU Loop Codes
  • 8-Bit Parallel or Serial Interface with Optional Hardware Mode
  • Muxed and Nonmuxed Parallel Bus Supports Intel or Motorola
  • Detects/Generates Blue (AIS) Alarms
  • NRZ/Bipolar Interface for Tx/Rx Data I/O
  • Transmit Open-Circuit Detection
  • Receive Carrier Loss (RCL) Indication (G.775)
  • High-Z State for TTIP and TRING
  • 50mARMSTransmit Current Limiter
  • JTAG Boundary Scan Test Port per IEEE 1149.1
  • Meets Latest E1 and T1 Specifications Including ANSI.403-1999, ANSI T1.408, AT&T TR 62411, ITU G.703, G.704, G.706, G.736, G.775, G.823, I.431, O.151, O.161, ETSI ETS 300 166, JTG.703, JTI.431, TBR12, TBR13, and CTR4


  • Central-Office Switches and PBX Interfaces
  • Integrated Multiservice Access Platforms
  • T1/E1 Cross-Connects, Multiplexers, and Channel Banks
  • T1/E1 LAN/WAN Routers
  • Wireless Base Stations

Key Specifications:

T/E Carrier & Packetized Products
Part Number Transmission Standard Functions Channels VSUPPLY
See Notes
DS21448  T1/E1/J1 LIU 4 3.3 $25.29 @1k
See All T/E Carrier & Packetized Products (88)

Pricing Notes:

This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


DS21448: Block Diagram
Block Diagram

More Information

New Product Press Release   2003-05-28 ]
Development Kit

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Information Index

Document Ref.: xxx Rev 3; 2006-01-23
This page last modified: 2009-10-13