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Control, Transmission, and Synchronization Interfaces

5-42 Issue 8.0 July 2002

If a BITS or stratum 1 traceable clock is not available at a node and

externally timed provisioning is desired, an external timing emulation (null

BITS) cable may be used to emulate BITS operation (Figure 5-28). The

external timing emulation cable connects TIMING OUT 1 to TIMING IN

PRI, or TIMING OUT 2 to TIMING IN SECY at the node.

Figure 5-28. Example of a Ring Application with All Nodes Provisioned

Externally Timed (with External Timing Emulation Cable)

For the nodes that distribute timing signals, the LAA18 TG3 (DS1) circuit pack

should be used. The LAA18 TG3 (DS1) circuit pack provides a timing signal (DS1

synchronization output) derived directly from the OC-48 high speed line. This

configuration supports either asynchronous or synchronous low speed interfaces

or any combination. The quality and source of the timing signals must be

engineered appropriately. The guidelines for choosing the timing source(s) and

the BITS clock configurations are beyond the scope of this document.

For more information about platform timing modes, refer to "Platform

Synchronization" in this section.

FT-2000

BITS

DS3/EC-1/OC-3

BITS

Independent

Clock

Externally Timed

P = TIMING IN PRI to TG3-1

S = TIMING IN SECY to TG3-2

1 = TIMING OUT 1 from TG3-1

2 = TIMING OUT 2 from TG3-2

Externally

Timed

Externally

Timed

BITS

DS3/EC-1/OC-3

External Timing Emulation Cable

Lucent Technologies FT-2000 OC-48 User Manual

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