To connect a Cisco PoE switch to a Rajant PoE capable device, you must turn off the PoE capability for this
port. You must set the “"power inline”“ setting of the port to ”“never.” For information about configuring
this port, refer to the following:
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12 2/25ew/configuration/gui
de/conf/PoE.html includes information for configuring the port.
Remarks:
Do not attempt to combine Cisco automatic PoE detection with the input port of Rajant passive PoE de-
vices used with the ME4, LX5, and JR2 models. Set the “power inline” setting of the port to “never”.
Contact a technical support representative for further information.
Page 1 of 1
G.5 Never Apply Power to the Data Input Port of a Rajant Mid-Span Power over
Ethernet (POE) Power Supply
IMPORTANT
IMPORTANT
This applies to all Rajant BreadCrumb models using passive PoE power supplies.
This applies to all Rajant BreadCrumb models using passive PoE power supplies.
Product TSB Notice No.: 03-100162-001
TECH SERVICE BULLETIN
Never Apply Power to the Data Input Port of a Rajant Mid-Span Power over Ethernet (POE) Power
Supply
Summary:
With exception to the Rajant VHDC-24V50W-GbE, never connect the data input port of any Rajant sup-
plied mid-span POE power supply to a POE powered data port. Rajant 10/100 POEs will not work prop-
erly, and Rajant 10/100/1000 POEs will be permanently damaged causing the Ethernet data link to fail.
Background:
Many Rajant BreadCrumb models including KM3, ME4, ME3, LX5, LX4 and the JR family do not support
802.3 af/at automatic power negotiation. These BreadCrumb models must be powered from Rajant-ap-
proved passive mid-span POE power supplies. Rajant mid-span POE power supplies do not support 802.3
af/at automatic power negotiation. With exception to the Rajant VHDC-24V50W-GbE, the data input port
of all other Rajant POE power supplies must never be connected to a POE powered data port.
The Ethernet data lines of the Rajant 10/100/1000 AC/DC mid-span POE power supply are protected by
low voltage TVS diodes. These protection diodes are intended to prevent damage to equipment from
short duration voltage transients, such as electrostatic discharge. The TVS diodes will fail to a permanent
short circuit condition if continuous DC voltage is applied. When the TVS diodes are damaged, the POE
data path will no longer work. The Ethernet data link will fail, or will never form.
Field Test:
Use the following procedure to test a Rajant mid-span POE for data path damage.
1. Remove the AC power cord from the Rajant POE.
2. Using two data cables, connect both the data INPUT and data plus POE OUTPUT port of the Rajant
POE to an unmanaged switch.
3. Confirm that a data link is formed by inspecting the link lights on the Ethernet switch ports.
4. If the POE does not form a data link on both ports of the Ethernet data switch, replace the POE with
a new one.
Mitigation:
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