~ National ~ Semiconductor - Al Kossow's Bitsavers

NSC Solutions for Layer 1
National's solution for Layer 1 consists of 3 CMOS transceivers,
which cover a wide variety of twisted-pair applications
for ISDN Basic Access. Each transceiver is capable of
transmitting and receiving 2 'B' channels plus 1 '0' channel,
and has mode selections to enable it to operate at either
end of the loop.
Transceiver Number 1
The TP3400 Digital Adapter for Subscriber Loops (DASL) is
a low-cost burst-mode transceiver for 2 wire PBX and private
network loops up to 6 kit in range. Scrambled Alternate
Mark Inversion coding is used, together with adaptive equalization
and timing-recovery, to ensure low bit error rates on
a wide variety of cable types. All activation and loop timing
control circuitry is also included.
Transceiver Number 2
The TP341 0 Echo-canceller Family is a set of 2-wire transceivers
designed to meet the rigorous requirements of the
'U' interface. Derived from a common basic architecture,
these devices will be compatible with the line-code and
framing structure speCifications of various PTT administrations
and with the U.S. standard.
BURST MODE (TeM) JII
FOR PBX LOOPS
ECHO CANCELLER JII
FOR 'U' INTERFACE
NSC ISDN Transceiver Chip Set
TP3401
DASL
Transceiver Number 3
The TP3420 'S' Interface Device (SID), is a 4-wire transceiver
which includes all the Layer 1 functions specified in
CCITT Recommendation 1.430. In addition, the TP3420 includes
noise filtering and adaptive equalization, as well as a
high resolution digital phase-locked loop, to provide transmission
performance far in excess of that specified in 1.430.
All Activation and '0' channel access sequences are handled
automatically without the need to invoke any action
from a microprocessor.
Digital Chip to Chip Interfaces
To retain the flexibility of interfacing components from this
chip set with a variety of other products, two digital interfaces
are provided on each device. One is for the synchronous
transfer of 'B' and '0' channel information in any of several
popular multiplexed serial formats. This means that National's
chip to chip interface is all encompassing of proprietary
frame structures such as the 10M, IDL, ST-BUS and more.
A second interface, for device mode control, e.g. power upl
down, setting loopbacks etc., uses the popular MICRO­
WIRE/PLUSTM. MICROWIRE/PLUS is a synchronous serial
data transfer between a microcontroller and one or more
peripheral devices. National's HPC and COPSTM microcontroller
families, together with a broad range of peripheral
devices, support this interface, which is also easy to emulate
with any microprocessor.
Popular Frame Structures
Addressed by NSC ISDN Devices
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