Corrective Maintenance—Service Circuits

The loss of a service circuit card can result in the inability of the system to process calls or in poor performance, as calls must wait for resources to become available.

In redundant systems, the redundant DTG-2 is in standby status during normal operation. If the primary DTG-2 fails, the other is automatically placed in active service to process calls. A minor alarm is triggered to indicate the need to service the failed DTG-2.

If a DTG-2 fails in a nonredundant system, calls cannot be completed, a major alarm is triggered, and a Phase 4 reboot occurs.

The DTG-2 card is mounted on the NBC3 card; it occupies the same slot as the NBC3.

Note the following:

• If the active NBC3 card switches to standby, the DTG-2 mounted on that NBC3 switches with it.
  
  
• An active DTG-2 does not switch with the NBC3 on which it is mounted if the standby DTG-2 has failed, or if there is no standby DTG-2.
  
  
• If the active DTG-2 switches to standby, the corresponding NBC3 does not switch with it.
  
  
• If you remove the NBC3 card, the DTG-2 mounted on that NBC3 is also removed.
  
  
• To remove the DTG-2 card, the NBC3 on which it is mounted must be removed.
  
  
• Remove the corresponding Combined Controller before removing the NBC3.
  
  

Note that in two cases listed above (bullets 2 and 3), the NBC3 and DTG-2 could be active on different sides, even though they are located on the same card. If you have to remove and replace a problem NBC3 or DTG-2, make certain you know the current active configuration of your system.

Note   All receiver cards must be placed into a single resource groups of the same type.

Failure of a single receiver card in a system with multiple receiver cards results in a lower grade of service, as fewer circuits are available to meet requests for receiver service. The system processes calls as long as at least one receiver card is available in the system.

The DCC is capable of maintaining the summation of seven PCM transmit samples. Since a conference port is only required when more than two participants are engaged in a call, the seven-sample summation allows up to eight callers to participate in a call.

Note   All DCCs must be placed into a single resource group.

Depending on the application, loss of the only DCC in a system may block call originations through the switch. If one DCC fails in a system with multiple DCCs, grade of service performance suffers but calls can be completed. Call setup time may increase as delays in mapping conference ports occur.

The CPA application is downloaded from hard disk to the CPA via the VCO/4K communication bus. Downloads are simultaneously broadcast to all configured CPA cards whenever a system is reinitialized (rebooted) from hard disk, or a directed download takes place when a CPA is reset and the download file on the hard disk is different than that stored in the CPA's RAM.

Note   All CPAs must be placed into a single resource group.

The number and type of CPA cards required by a system is specified by the customer based on anticipated traffic and the call scenario.

• Period between communication bus interrupts is greater than 2.5 seconds, indicating a communication bus failure
  
  

If the yellow LED illuminates on a service circuit card during normal system operation, use the Card Maintenance Menu to reset the card with the Change Status command (refer to the Cisco VCO/4K System Administrator's Guide). If the Change Status command fails, remove the card from the backplane and reseat it. If the red LED illuminates, remove and replace the card (refer to the Cisco VCO/4K Card Technical Descriptions).

If a service circuit card has been mounted in the wrong slot or has not been configured in the database, the card's green LED is illuminated, and the system log contains error messages indicating a wrong card.

In addition to illuminating appropriate status LEDs, all system and card alarm conditions are appropriately identified in the log, such as CARD ALRM SET, CARD ALRM CLRD, MIN ALARM SET, MIN ALRM CLRD.

Note   Use the Card Maintenance menu from the Maintenance Menu to place the desired service card(s) in Diagnostic (D) mode. This test function does not work unless the card has been placed in Diagnostic mode.

Refer to the Cisco VCO/4K System Administrator's Guide for detailed instructions on using this function.

To change the current status of a DTG-2 card, reset the active card from the Card Maintenance menu. Select the active DTG-2 and use the Change Status (C) function to reset the card to Out-of-Service (O) status.

Note   VCO/4K systems do not allow a DTG-2 to be marked OOS if it is the only DTG-2 currently in service.

The system automatically forces a standby DTG-2 card to active status, and places the active DTG-2 in out-of-service status. A minor alarm occurs, but is cleared when the DTG-2 cards have assumed their new operating status. To reset the out-of-service DTG-2, use the Change Status (C) function to reset the card to Active (A) status. The DTG-2 is reset and placed in standby status. This may take up to four minutes. The minor alarm for the card is cleared.

If a card is improperly configured, it may fail to function properly. Verify configuration settings before installing a replacement service circuit card in the system. Always check the firmware version against the requirements specified in the configuration portion of the Cisco VCO/4K System Software Release Notes. If the wrong version of firmware is installed, the system will not operate properly.