Cisco Aironet 1200 Series

Field Notice: Cisco Aironet AP1200: Failure to Power Up With 802.11a Radio Installed

December 01, 2004

Products Affected

  • AIR-AP1220A-A-K9

  • AIR-AP1220A-J-K9

  • AIR-AP1220A-S-K9

  • AIR-AP1220A-T-K9

  • AIR-AP1230A-A-K9

  • AIR-AP1230A-J-K9

  • AIR-AP1230A-S-K9

  • AIR-AP1230A-T-K9

  • AIR-RM20A-A-K9

  • AIR-RM20A-J-K9

  • AIR-RM20A-S-K9

  • AIR-RM20A-T-K9

Problem Description

The Cisco Aironet AP1200 series with the AIR-RM20A-x-K9 802.11a radio module installed, may, under certain and in specific applications, require multiple attempts to power up when receiving power over Ethernet from Cisco Catalyst switches. This hardware incompatibility has only been observed in applications where temperatures are higher than room temperature, a condition that is consistent with mounting devices in NEMA-type enclosures.


When powering up, the AIR-RM20A-x-K9 802.11a module draws a greater amount of current than do 802.11b and 802.11g modules. This greater draw coupled with higher than room temperature environments can result in the start-up section of the AP power supply to have a lower threshold on its fault protection circuit.

Problem Symptoms

When in this incompatible state, the access point will re-attempt to source power from the switch approximately once every 15 seconds. After some number of retries (ranging from one to 100 retries or 15 seconds to 25 minutes) the device will power up and function normally until power is cycled. If power to the device is interrupted, this power acquisition process is very likely to be similar to the initial power up process. The switch CLI will indicate an error showing that the switch power is applied to the link, but the ethernet link is not detected. There is no evidence that this power up condition gets better or worse over time, or that the component parts degrade over time. There is no evidence of any permanent hardware damage to either the in line powering equipment or the access point due to this condition.


Systems which contain all conditions listed for this issue may not necessarily exhibit this issue, due to the combination of component tolerances on each of the products involved. If this issue does occur, it is only when power is initially applied to the AP1200. In other words, this is not a component or age sensitive issue, and an RMA will not provide any benefit.

If removing the RM20A module from the access point alleviates the power up condition immediately, please contact Cisco TAC for resolution.


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CSCef25030 (registered customers only)

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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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