Chapter 10. Designing a Network

A typical private network is shown in Figure 7. It is necessary to know if the carrier can supply a source of Stratum 1 traceable timing. For purposes of this example, the carrier identifies two T1 trunks at locations A and B that will be timed by the network, and that can be traced to the carrier's Stratum 1 source.

At location A, a Larus STS 5400 Synchronization Timing System bridges one of the incoming trunks timed by the network. The outputs of the synchronization system drive the clock inputs of the multiplex equipment.

Another STS 5400 Synchronization Timing System at location B is connected in the same manner as at location A.

If the trunk feeding the STS 5400 system at either end has error bursts or short outages, the clock output of the STS 5400 system will continue without any impairments. Should the outage last longer than the worst case holdover time (7 hours), a slip may occur, and up to four more slips may occur within the next 24 hours. Once the trunk is restored to service, the STS 5400 system calculates a new phase and frequency reference, and returns to the tracking mode. No additional slips, due to the new frequency acquisition, will occur while the system is returning to the tracking mode.

The use of an STS 5400 Synchronization Timing System at each location will assure reliable timing for private networks such as this.

The 5400 system adds the capability of interfacing with remote or local terminals. The remote interface port is connected to the office network management system for status reporting and control of the system through the use of TL1 or menu-driven commands and responses. The local interface port may be used with any "dumb" terminal or PC emulating a terminal to provide the same functions as the remote interface.

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