If your ENTTEC device is working when plugged into a DC power source but does not work when plugged into your PoE power source, there are two key areas to check:
Cable Length & Termination
In line with the IEEE 802.3af specification, ENTTEC recommends an absolute maximum network cable length of 100m (333 feet) terminated to an RJ45 or EtherCon connector in accordance with the EIA/TIA-568-B standard.
If your installation requires a cable length higher than 100m, an 802.3af compliant PoE repeater or second network switch must be used to ensure no single cable length is longer than 100m (333feet).
To date, ENTTEC has successfully tested the following cable types in the house:
- CAT5
- CAT5e
- CAT6
- CAT6a
- CAT7
It is recommended that multiple cables are tried when troubleshooting to ensure that the chance of damaged cabling is ruled out.
PoE Supply
PoE sources often take the form of network switches or PoE injectors.
ENTTEC’s PoE products are compliant with the IEEE802.3af standard with a minimum Input voltage of >= 42V. (nominal 48v), these are considered to be active PoE devices.
Active PoE means that the ENTTEC device will check the power coming in, and if it doesn’t meet the device requirements, it won’t power up.
PoE standards have been optimised for safety. In addition to a safe voltage range, the devices must communicate according to established procedures. Before providing the supplying voltage, the PoE power supply unit tests the connection. 802.3af then does a “handshake”, meaning it checks to ensure the power is compatible between the PoE sender and the ENTTEC device. The ENTTEC device will not power up if the receiver does not acknowledge it.
Passive PoE usually refers to any device using PoE that is not 802.3af or 802.3at. This often includes devices such as security cameras and radio antennas that run on 24V PoE. Passive PoE does not perform a handshake, so it is essential to know the PoE voltage your device requires before plugging in your Ethernet cable and powering the system up. If the device is connected to the wrong voltage, you may cause permanent electrical damage to the device. ENTTEC has implemented active PoE to prevent damage from occurring to your device.
Check that your PoE source is IEEE802.3af or IEEE802.3at compatible to ensure it is capable of performing the PoE handshake procedure with your ENTTEC device to begin providing power as illustrated below:
I cannot get my PoE network switch to connect to my non-PoE ENTTEC device.
All non-PoE ENTTEC devices require a local power supply to operate.
However, under certain circumstances, it has been witnessed that specific models of network switches require PoE functionality to be disabled when non-PoE devices are connected.
If power negotiation fails, some models of network switches can disable the output entirely (both power and data).
When the ports PoE connection is removed, the power negotiation process isn’t required, so nothing stops the link.
For best practice, ENTTEC only recommends enabling PoE on your network switch when used for a PoE device.