
PRELIMINARY
XRT86SH221
20
REV. P1.0.5
SDH-TO-PDH FRAMER/MAPPER WITH INTEGRATED 21-CHANNEL E1 SH LIU
2.0
APPLICATIONS AND PHYSICAL INTERFACE GENERAL OVERVIEW
The XRT86SH221 (Voyager-Lite) is a highly integrated, monolithic device designed for cost-sensitive SDH to
PDH mapper applications. Voyager-Lite supports all the framing, mapping and grooming functions required for
E1 aggregation to STM-1 via standard VC-12 to AU-3 and AU-4/TUG-3 mapping protocols. The device
generates and terminates all SDH Regenerator Section, Multiplexer Section and Path Overhead including the
low-order Virtual Container (VC) Path Overhead. E1 framing is transparent; therefore, the device neither
generates nor terminates the E1 frame.
Voyager-Lite includes a standard Telecom Bus interface to an SDH (STM-0/STM-1) Framer /Mapper with SDH-
to-PDH Desynchronizer, VC-12/TU-12 Mapper, VC-12 Cross-Connect and a 21-channel E1 Short Haul LIU with
integrated egress frame synchronizer for E1 bit-retiming. Voyager-Lite also provides alarm and performance
monitoring for all STM-1 and VC-12 overhead in compliance with ITU-T G.783 standards. Section and Path
overhead may be inserted/extracted via serial interfaces provided in transmit and receive directions.
The 21-channel E1 Short Haul LIU provides line termination and generation in compliance with G.703
standards, supporting E1 (2.048Mbps) 75
and 120
applications. The LIU receiver includes adaptive
equalizer, clock and data recovery, and HDB3 decoding with performance monitoring of Loss of Signal, Line
Code Violations and Excessive Zeros. The LIU transmitter includes HDB3 encoder, transmit pulse shaping and
line driver. The LIU also provides a half-duplex jitter attenuator which may be applied in either the transmit or
receive data path.
E1 spans are mapped to VC-12/TU-12 via the Virtual Container (VC) and Tributary Unit (TU) mapper. VC-12
grooming support provided for both transmit and receive directions on a per E1 basis via the integrated, full-
duplex 21x21 VC-12 Cross-Connect. The SDH framer/mapper supports generation and termination of STM-1
Section and Path overhead and also performs SDH to PDH desynchronization.
A single Voyager-Lite performs mapping of 21 asynchronous E1 spans to either VC-12/TU-12/TUG-2/VC-3/AU-
3/STM-0 or VC-12/TU-12/TUG-2/TUG-3/STM-0. VC mapping to STM-1 requires (3) Voyager-Lite devices with
one acting as "master" framer and two acting as "slave" framers. In this configuration, Voyager-Lite performs all
the necessary framing, pointer processing and mapping functions required for mapping of 63xE1 spans to either
VC-12/TU-12/TUG-2/VC-3/AU-3/STM-1 or VC-12/TU-12/TUG-2/TUG-3/VC-4/AU-4/STM-1.
F
IGURE
2. A
PPLICATION
D
IAGRAM
XRT86SH221
21 Channel
VC Mapper IC
XRT86SH221
21 Channel
VC Mapper IC
XRT86SH221
21 Channel
VC Mapper IC
XRT91L30
STM-1
Transceiver IC
63 Channels of
E1 Line Signals
Shared Transmit Direction
Byte-Wide Bus, Clocked at
19.44MHz
STM-1
Data via LVPECL
Shared Received Direction
Byte-Wide Bus, Clocked at
19.44MHz