TLH11924

PRELIMINARY

July 1994

TP3404

Quad Digital Adapter for Subscriber Loops (QDASL)

General Description

The TP3404 is a combination 4-line transceiver for voice

and data transmission on twisted pair subscriber loops typi-

cally in PBX line card applications It is a companion device

to the TP340123 DASL single-channel transceivers In

addition to 4 independent transceivers a time-slot assign-

ment circuit is included to support interfacing to the system

backplane

Each QDASL line operates as an ISDN ‘‘U’’ Interface for

short loop applications typically in a PBX environment pro-

viding transmission for 2 B channels and 1 D channel

Full-duplex transmission at 144 kbs is achieved on single

twisted wire pairs using a burst-mode technique (Time Com-

pression Multiplexed) All timing sequences necessary for

loop activation and de-activation are generated on-chip

Alternate Mark Inversion (AMI) line coding is used to ensure

low error rates in the presence of noise with lower emi radia-

tion than other codes such as Biphase (Manchester) On

24 AWG cable the range is at least 18 km (6k ft)

Features

4 COMPLETE ISDN PBX 2-WIRE DATA TRANSCEIVERS

INCLUDING

Y

Quad 2 B plus D channel interface for PBX ‘‘U’’

interface

Y

144 kbs full-duplex on 1 twisted pair using Burst Mode

Transmission Technique

Y

Loop range up to 6 kft ( 24AWG)

Y

Alternate Mark Inversion coding with transmit Pulse

Shaping DAC Smoothing Filter and scrambler for low

emi radiation

Y

Adaptive line equalizer

Y

On-chip timing recovery no external components

Y

Programmable Time-Slot Assignment TDM interface for

B channels

Y

Separate interface for D channel with Programmable

Sub-Slot Assignment

Y

4096 MHz master clock

Y

4 loop-back test modes

Y

Y

5V operation

Y

28-pin PLCC package

Block Diagram

TLH11924 – 1

TRI-STATE

is a registered trademark of National Semiconductor Corporation

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A