Cisco ONS 15800 Series DWDM Platforms

Field Notice: 15808-FAN-TRAY Version (800-15928-02) May Result in False Alarms on 15808-SCU Modules Due to Incorrect Fan Low Current Threshold Settings

January 12, 2004

Products Affected


Top Assembly Part Number




Affects 800-15928-02 and later




Problem Description

The default alarm threshold for fan current low, set on the 15808-SCU to monitor fan operations, may be set too high for the current 15808-FAN-TRAY (800-15928-02 and later) which may result in a false alarm on the 15808-SCU=.


By default the fan current low threshold is set at 600 mA on the 15808-SCU, but with the latest revision of the 15808-FAN-TRAY (800-15928-02 and later) the fan current low threshold should be set at 500 mA to reflect improved efficiencies in the 15808-FAN-TRAY= (800-15928-02 and later).

Problem Symptoms

When using the 15808-FAN-TRAY (800-15928-02 and later), users may encounter false alarms on the 15808-SCU due to a incorrectly specified fan current low thresholds on the 15808-SCU. This is most commonly seen at temperatures in excess of 55C.


For systems that are using the 15808-FAN-TRAY (800-15928-01) the default value should remain at 600 mA. If the 15808-FAN-TRAY (800-15928-01) is replaced with the latest version of hardware (800-15928-02 or later), then the fan current low threshold should be reduced to 500 mA using any of the Cisco Photonics Element Managers or the Cisco Craft Terminal (CPLT/CWD).

Use the following steps to verify or modify the fan current low threshold using Cisco Wave Director (CWD):

  1. Connect to the Network Element

  2. Expand the card tree up to the SCU you wish to view

  3. Expand the SCU tree and select Current

  4. Within the right window of CWD, select Fan Operating Current n , right click and select Open from the menu

  5. From the Setting IOGen param pop up window, click on Low Thr and set the Threshold Value to 500 mA.


For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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