
TL/H/11924
T
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 TP3401/2/3 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 kb/s 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
Y
24 AWG cable the range is at least 1.8 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 kb/s full-duplex on 1 twisted pair using Burst Mode
Transmission Technique
Y
Loop range up to 6 kft (
Y
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
4.096 MHz master clock
Y
4 loop-back test modes
Y
MICROWIRE
TM
compatible serial control interface
Y
5V operation
Y
28-pin PLCC package
Block Diagram
TL/H/11924–1
TRI-STATE
é
is a registered trademark of National Semiconductor Corporation.
MICROWIRE
TM
is a trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation
RRD-B30M115/Printed in U. S. A.