
TL/H/11725
T
November 1992
TP3406
DASL Digital Adapter for Subscriber Loops
General Description
The TP3406 is a complete monolithic transceiver for data
transmission on twisted pair subscriber loops. It is built on
National’s double poly microCMOS process, and requires
only a single
a
5 Volt supply. Alternate Mark Inversion (AMI)
line coding, in which binary ‘1’s are alternately transmitted
as a positive pulse then a negative pulse, is used to ensure
low error rates in the presence of noise with lower emi radia-
tion than other codes such as Bi-phase (Manchester).
Full-duplex transmission at 144 kb/s is achieved on a single
twisted wire pair using a burst-mode technique (Time Com-
pression Multiplexed). Thus the device operates as an ISDN
‘U’ Interface for short loop applications, typically in a PBX
environment, providing transmission for 2 B channels and 1
D channel. On
Y
24 cable, the range is up to 800 meters.
System timing is based on a Master/Slave configuration,
with the line card end being the Master which controls loop
timing and synchronisation. All timing sequences necessary
for loop activation and de-activation are generated on-chip.
Selection of Master and Slave mode operation is pro-
grammed via the Microwire Control Interface.
A 2.048 MHz clock, which may be synchronized to the sys-
tem clock, controls all transmission-related timing functions.
Features
Complete ISDN PBX 2-Wire Data Transceiver including:
Y
2 B plus D channel interface for PBX U
ê
Interface
Y
144 kb/s full-duplex on 1 twisted pair using Burst Mode
Y
Loop range up to 800 meters (
Y
24AWG)
Y
Alternate Mark Inversion coding with transmit filter and
scrambler for low emi radiation
Y
Adaptive line equalizer
Y
On-chip timing recovery, no external components
Y
Standard TDM interface for B channels
Y
Separate interface for D channel
Y
2.048 MHz master clock
Y
Driver for line transformer
Y
4 loop-back test modes
Y
Single
a
5V supply
Y
MICROWIRE
TM
compatible serial control interface
Y
Applications in:
PBX Line Cards
Terminals
Regenerators
Y
Available in 28-pin PLCC Package
Block Diagram
TL/H/11725–1
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.