Metrodata Limited

The APX UNI interface modules enable connection to ATM services, either as network or switch ports, or are used as trunk ports for non-ATM applications. Each UNI modules provide a single ATM interface port, with the range being standards compliant and covering all standard Telecom data rates.

The APX resilient STM-1/OC-3 UNI module offers a dual STM-1/OC-3 155Mbps fibre port supporting native ATM cells, although only one port is active at a time. This allows the AP to connect with other ATM equipment with an STM-1/OC-3 UNI port, either directly or via an STM-1/OC-3 G.703 155Mbps leased line. This module can also be used as an uplink for connection to another AP chassis at the other end of an STM-1/OC-3 G.703 155Mbps leased line.

The resilient STM-1/OC-3 UNI module ensures high availability through the use of a backup circuit to minimise network downtimes. The resilient SDH module uses Automatic Protection Switching, operating in 1+1 mode, whereby if a fault is detected on the main, or working link, the interface will automatically switch to use the backup, or protection link. Once a fault has been detected switching will occur and service will resume within 50ms. Line monitoring is not just limited to Loss of Signal allowing operation in networks where media converters will continue to provide a light source even in the event of a link breakage.

Each UNI module performs physical layer and ATM layer functions including framing, alarm processing and cell delineation. Flexible clocking options remove network synchronisation problems. Status LED's are provided to indicate that real traffic is passing across the ATM interface.

Management and configuration of this module is achieved via the simple menu driven user interface. Extensive statistics and status information are gathered at all layers and are available to the user interface as a diagnostic aid. OAM alarm and loopback functions are supported as per UNI 3.1

Additionally SNMP Traps may be generated to indicate Link Up/Down. These modules can be "Hot Swapped" to ease maintenance, with replacement modules recovering immediately without further configuration.

This module has the following features:

• standards compliant STM-1/OC-3 155Mbps interfaces with a choice of fibre interfaces
  
• can be used in any AP chassis
• hot swap interface module, with configuration automatically loaded onto the replacement module

The choice of fibre interfaces is as follows:

• MM: pair of dual SC multimode fibre interfaces, max operating distance 2km-5km
• SMSH: pair of dual SC singlemode fibre interfaces, max operating distance 15km-30km
• SMLH: pair of dual SC singlemode fibre interfaces, max operating distance 40km-70km