Exar
Corporation 48720 Kato Road, Fremont CA, 94538
(510) 668-7000
FAX (510) 668-7017
www.exar.com
á
PRODUCT BRIEF
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER
XRT94L31
APRIL 2004
GENERAL DESCRIPTION
REV. P1.0.0
The XRT94L31 is a highly integrated SONET/SDH
terminator designed for E3/DS3/STS-1 mapping/de-
mapping functions from either the STS-3 or STM-1
data stream. The XRT94L31 interfaces directly to the
optical transceiver.
The XRT94L31 processes the section, line and path
overhead in the SONET/SDH data stream. The
processing of path overhead bytes within the STS-1s
or TUG-3s includes 64 bytes for storing the J1 bytes.
Path overhead bytes can be accessed through the
microprocessor interface or via serial interface.
The XRT94L31 uses the internal E3/DS3 De-
Synchronizer circuit with an internal pointer leak
algorithm for clock smoothing as well as to remove
the jitter due to mapping and pointer movements.
These De-Synchronizer circuits do not need any
external clock reference for its operation.
The SONET/SDH transmit blocks allow flexible
insertion of TOH and POH bytes through both
Hardware and Software. Individual POH bytes for the
transmitted SONET/SDH signal are mapped either
from the XRT94L31 memory map or from external
interface. A1, A2 framing pattern, C1 byte and H1, H2
pointer byte are generated.
The SONET/SDH receive blocks receive SONET
STS-3 signal or SDH STM-1 signal and perform the
necessary transport and path overhead processing.
The XRT94L31 provides a line side APS (Automatic
Protection Switching) interface by offering redundant
receive serial interface to be switched at the frame
boundary.
The XRT94L31 provides 3 mappers for performing
STS-1/VC-3 to STS-1/DS3/E3 mapping function, one
for each STS-1/DS3/E3 framers.
A PRBS test pattern generation and detection is
implemented to measure the bit-error performance.
A general-purpose microprocessor interface is
included for control, configuration and monitoring.
FEATURES
Provides DS3/ E3 mapping/de-mapping for up to 3
tributaries through SONET STS-1 or SDH AU-3
and/or TUG-3/AU-4 containers
Generates and terminates SONET/SDH section,
line and path layers
Integrated SERDES with Clock Recovery Circuit
Provides
SONET
frame
descrambling
Integrated Clock Synthesizer that generates 155
MHz and 77.76 MHz clock from an external 12.96/
19.44/77.76 MHz reference clock
Integrated 3 E3/DS3/STS-1 De-Synchronizer circuit
that de-jitter gapped clock to meet 0.05UIpp jitter
requirements
Access to Line or Section DCC
Level 2 Performance Monitoring for E3 and DS3
Supports mixing of STS-1E and DS3 or E3 and
DS3 tributaries
E3 and DS3 framers for both Transmit and Receive
directions
Complete Transport/Section Overhead Processing
and generation per Telcordia and ITU standards
Full line APS support for redundancy applications
Loopback support for both SONET/SDH as well as
E3/DS3/STS-1
Boundary scan capability with JTAG IEEE 1149
8-bit microprocessor interface
3.3 V ± 5% Power Supply; 5 V input signal
tolerance
-40°C to +85°C Operating Temperature Range
Available in a 504 Ball TBGA package
scrambling
and
APPLICATIONS
Network switches
Add/Drop Multiplexer
W-DCS Digital Cross Connect Systems