Network expansion

The explosion in demand for telecommunications services has resulted in the implementation of complex networks. These often contain a large number of network elements, all of which must be synchronised to ensure that the quality of service meets the international standards and the demands of network users.

Very often, extra output capacity is required at the network nodes to synchronise all its elements and it is thus necessary to implement expansion equipment.

To meet this requirement, Oscilloquartz has introduced two synchronisation distribution units (SDU), OSA 5533C SDU and OSA 5530B SDU.

These units are designed to provide maximum number of outputs from one or two synchronisation signal(s). The units are ideally suited to synchronisation distribution requirements in SDH or SONET as well as cellular switch nodes where a stable reference is available.

The units provide an economic approach to distribution of synchronisation references to network elements, such as switches, cross-connects and multiplexers.

Well-proven design
All Synchronisation Distribution Units use the well proven modular approach from Oscilloquartz, and are totally maintenance-free. Partially equipped configurations are available with upgrade capability to the full configuration. All plug-in cards can be replaced in a hot condition.

Alarms and Monitoring
The models include a Monitoring and Alarms Controller (MAC) card or a Remote Management Unit (RMU). This card concentrates all shelf alarms, provides visual indicators, relay contacts for in-station or central monitoring via a RS232c or TCP/IP port. It also features Urgent and Non-Urgent indications as well as a Receiving Attention function to acknowledge active alarms and an audible alarm. With Oscilloquartz' LM (Local Manager) or SyncView (network management system from Oscilloquartz), the user can configure the system, receive spontaneous events and view the alarm list.

Output Flexibility
Various output interface modules are available each with 16 outputs. Interface types include 64kbit/s CC, T1 (1.544 Mbps), E1 (2.048Mbps), 2.048, 5, and 10 MHz and many more.

The units offer a highly versatile choice of output connectors that can be configured in groups of four at the factory or in the field. The choice of connectors includes D type for 100 ohm, 120 ohm or 133 ohm ports and BNC, 1.6/5.6, 1.0/2.3 or type 43 for 75 ohm ports.

Several hundreds of outputs can be achieved by connecting several SDU's in either parallel or serial.

The SDU's protected front-end accepts two external synchronisation reference inputs at 2.048MHz and provides up to 96 1:1 protected or unprotected synchronisation outputs, which are referenced to the selected synchronisation input.

Should the selected input fail, the unit will automatically switch to the secondary synchronisation input. Output phase coherence after changeover operations is maintained well below 1/8UI (61ns), typically 5ns. This is important for SDH/SONET networks that are more sensitive to phase variations. Switchover is normally made automatically. Manual switching is done via the Local Management software.

The OSA 5530B SDU also includes redundant output ports to drive further SDU's.

The equipment communicates with a local terminal or a PC for alarm reporting and equipment control. When used in conjunction with an OSA 5548B SASE, the unit can be managed by the SyncView^® synchronisation network management system for alarm reporting and control functions.