Field Notice: FN74099 - IW9165: Catalyst IW9165 Access Points May Not Failover to PoE When Dual Powered - Workaround Provided

When DC power is lost, Cisco Catalyst IW9165 Access Points fail to properly boot after switching to Power over Ethernet (PoE) power.

A Cisco Catalyst IW9165 Access Point accepts DC power input and PoE input. DC power input takes priority over PoE input when both are supplied simultaneously. When DC power input is lost, the expected behavior is for the access point to switch to PoE power and reboot.

Cisco internal testing has identified an issue when an access point is connected to both DC power input and PoE. Customers may encounter a voltage reference issue when the DC power input has a common reference to other PoE-powered devices connecting to the PoE power source.

The access point fails to properly boot after switching to PoE power when DC power is lost, but the DC- remains referenced (connected) to the power source of other PoE-powered devices.

Restoring DC power to the access point or disconnecting the DC power input (breaking the DC- reference) will allow the access point to boot normally.

No permanent issue to the access point has been observed during Cisco internal testing of this issue.

The following conditions may lead to this issue:

• The access point (device 1) must be connected to a DC power source and a PoE power source.
• Another PoE-powered device (device 2) must be connected to the PoE power source.
• The DC- of the DC power source for device 1 and device 2 are connected.

The issue will be encountered when the DC+ of the DC power source for device 1 and device 2 is opened (disconnected) while the DC- remains connected—for example, a single pole fuse or a circuit breaker is opened that only interrupts DC+.

Customers may also encounter this issue when using the IW-PWRADPT-MFIT4P= V01 power adapter. The metal chassis of the power adapter is connected to DC-. The issue may occur if either of the following conditions are present:

• The chassis of the adapter connected to device 1 is touching any surface that connects to DC- of the power input to device 2.
• Device 2 is connected to another IW-PWRADPT-MFIT4P= V01 power adapter, and the chassis of the two power adapters have electrical continuity between them, either by directly touching or touching a common conductive surface.

The following workarounds are available to avoid the issue:

• Connect the Cisco Catalyst IW9165 device to only a single power source, either DC or PoE power. A DC redundancy module sized for the access point power draw can be used if power source redundancy is desired.
• Isolate the DC- between the Cisco Catalyst IW9165 device and other devices that are connected to the same PoE power-supplying device.
• Add a Schottky diode to the DC- side of the power supply to the Cisco Catalyst IW9165 access point. The diode must be rated for DC-blocking voltage of 100V, a maximum forward current of 2A, and an operating temperature from -40 degrees Celsius to 85 degrees Celsius.
• If customers are using the IW-PWRADPT-MFIT4P= power adapter, they should isolate the power adapter using a dielectric material for mounting.

The product model can be identified by referencing the label on the access point or obtaining the product identifier (SKU/PID). Models that begin with “IW9165E” or “IW9165DH” and the version identifier “V01” are affected.

The PID and version identifier are also located on the packout label on the product carton.

Example of Cisco Catalyst IW9165E Product Label with PID and Version Identifier

The PID shown in the photo begins with “IW9165E,” and the version identifier is “V01.” This product is affected.

Example of Cisco Catalyst IW9165D Product Label with PID and Version Identifier

The PID shown in the photo begins with “IW9165DH,” and the version identifier is “V01.” This product is affected.

Example of Cisco Catalyst IW9165E Product Carton Packout Label

The PID shown in the photo begins with “IW9165E,” and the version identifier is “V01.” This product is affected.

Example of Power Adapter IW-PWRADPT-MFIT4P= Label with PID and Version Identifier

The PID shown in the photo is “IW-PWRADPT-MFIT4P=,” and the version identifier is “VVV.” Products with “V01” in place of “VVV” are affected. “V02” with insulated mounting hardware properly installed are not affected.