DESCRIPTION
The DS21348 is a complete selectable E1 or T1 LIU for short-haul and long-haul applications. Throughout the data sheet, J1 is represented wherever T1 exists. Receive sensitivity adjusts automatically to the incoming signal and can be programmed for 0dB to 12 dB or 0dB to 43dB for E1 applications and 0dB to 30dB or 0dB to 36dB for T1 applications.

FEATURES
Complete E1, T1, or J1 line interface unit(LIU)
Supports both long-haul and short-haul trunks
Internal software-selectable receive-side termination for 75Ω/100Ω/120

3.3V power supply
32-bit or 128-bit crystal-less jitter attenuator requires only a 2.048MHz master clock for both E1 and T1 with 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
50mA (rms) current limiter