
Configuration Procedures and Considerations
# P0602477 Ver: 3.1.11 Page 265
TMS Computer Telephony (CT) Bus Clocking
For the purpose of synchronizing CT communications across the PCM highways of
each chassis and ATM switching fabric between chassis, each node is configured to
use primary and secondary reference clocks from any one of several sources. (For
configuration, see Synclist Configuration Section on page 119.) The TDM backplane
bus includes two reference clocks (REFCLK_A and REFCLK_B). Each TMS can
drive or receive either or both of these clocks, using any single source on a particular
TMS. However, the most reliable degree of redundancy is obtained when the
reference sources reside in different spans, DCCs, TMSs, and chassis, if system scale
permits.
Digital systems use the 8 kHz frame sync from a DCC span. Any DCC on the node
can be configured as the source of either REFCLK_A or REFCLK_B. Analog
systems use a local 8 kHz reference on a TMS. The local reference oscillator on any
TMS can be used for either reference clock.
TMS
(Slot 1)
DCC (Slot 4)
Spans
Frame Sync
(8 kHz)
Local 8 kHz
Reference
(Analog
Systems)
DCC
(Slot 3)
Mux
Pri
Sec
Mux
DCC
(Slot 2)
NIC
(Pri)
NIC
(Sec)
TMS
(Slot 2)
TMS
(Slot 3)
REFCLK_A
REFCLK_B
a
b
cd
Source
Timing
Clock
Enables
Clock
Monitors,
Selectors,
and
Multipliers
TMS
(Slot 4)
DCC
(Slot 1)
VRC
VRC
Rear
Panel
EXT
CLK A
EXT
CLK B
Komentáře k této Příručce