Symmetricom SSU-2000 User Manual page 45

Chapter 1 Product Overview
SSU-2000 Family of Modules
Japanese Composite Clock Output Module
The J/CC Output module generates 20 non-summable signal pairs (TTIP and
TRING signal pairs). Each output is a transformer-coupled symmetrical pair. Each
output pair can be turned off independently of other channels. These outputs are
independently configurable for phase delay from 0 to 3.4 μs in 8 steps.
In subtending mode, the Output module's signals are byte and polarity phase
aligned with the 4 kHz clock signal from the Japanese Composite Clock Input
module. This 4 kHz clock signal ensures that the phase of the composite clock
output signal follows the phase of the composite clock input reference signal. See
Japanese Sine Wave Output Module, on page 219 for more information.
Japanese Sine Wave Output Module
The J/SW Output module uses one of three 4 kHz clocks from the SSU-2000 main
chassis backplane to generate a phase-locked reference signal for the
synchronized clock output signals. The phase-locked signal is used to generate 20
software selectable outputs of either 6.312 MHz or 1.544 MHz for distribution to
large networks. See Japanese Sine Wave Output Module, on page 219 for more
information.
Line Re-timing Unit (LRU)
Symmetricom offers two Line Re-timing modules for the SSU-2000: one for DS1
signals and one for E1 signals. The LRU is comprised of a Line Re-timing module
(LRM) and a Cut-Through Assembly (CTA). The DS1 LRU is available in both a
two-port (dual) and four-port (quad) version. The E1 LRU is available in a four-port
(quad) version. For more information, see DS1 Line Retiming Unit (LRU), on page
245 and E1 Line Re-timing Unit, on page 258.
The DS1 LRU inserts DS1 signals on both sides of a DSX-1 panel in a Central
Office. Side 1 of the DS1 re-timer provides "3R" (Re-shape, Re-amplify, and
Re-time) for the DS1 signal to a client Network Element. When the LRU receives a
DS1 data stream, it re-times the data with the transmit clock signal. The clock signal
is inserted into the DS1 line route between two DS1 path-terminating elements.
Side one is the direction in which timing is applied. Side 1 contains the DS1 line
performance reporting and AIS generator. AIS is not generated when the port is set
to Unused/Off. Side 2 provides "2R", which Re-shapes and Re-amplifies
(regenerates) the DS1 signal from the client Network Element. Side 2 does not
provide performance monitoring or AIS generation.
The E1 LRU provides four independent retimed lines (signals) and automatically
detects framing, and can be provisioned for AMI or HDB3 codes. The LRM inserts
E1 signals on both sides of a system connectivity panel in a Central Office. Side 1 of
the E1 re-timer provides "3R" (Re-shape, Re-amplify, and Re-time) for the E1 signal
to a client Network Element.
12713020-002-2 Revision F.01 – January 2007 SSU-2000 User's Guide 45