Power over Ethernet connector selection and connection ?

[balagbc]

hi all,
i have conflict over selecting POWER OVER ETHERNET connector and connection between connector and controller. i need to send +12v and data in same RJ45 connector. i select some POE+ magnetic jack connector. but i dont know how to connect 12v and data line.if i transmit both power and data will it get affect each other? Reply and give suggestion about POWER OVER ETHERNET.
thanks in advance.

 

[KlausST]

Hi,

Power over Ethernet (PoE) is a fixed standard (with multiple solutions).

Either you read PoE specification, or use your own system, then don´t call it Power over Ethernet. I don´t think 12V is within PoE standard.

PoE uses the same ethernet connetors as without PoE. But you need special PoE transformers with center tap.

With PoE you need a communication (switched resistors with different values) of both PoE power supply and ethernet device.

Klaus

 

[FvM]

IEEE 802.3 2012, Clause 33 is describing two alternative schemes for implementing PoE with 10/100 Mbit twisted pair connections



See also: https://en.wikipedia.org/wiki/Power_over_Ethernet

Compliant PSE has to check the load condition to avoid damaging standard non-PoE aware equipment, which may involve a common mode short or 75 ohm resistor to ground.

 

[balagbc]

Hi,

Power over Ethernet (PoE) is a fixed standard (with multiple solutions).

Either you read PoE specification, or use your own system, then don´t call it Power over Ethernet. I don´t think 12V is within PoE standard.

PoE uses the same ethernet connetors as without PoE. But you need special PoE transformers with center tap.

With PoE you need a communication (switched resistors with different values) of both PoE power supply and ethernet device.

Klaus

Dude thats why iam confusing over selecting center tapping ethernet connector. if i select the POE connector will it cause change in connection in our circuit. do we need special power circuit to convert power,transmitting over the ethernet .

if i have some voltage in my pcb should i connect the supply voltage directly in pin 4,5 and 7,8 or with any other circuit?

- - - Updated - - -

IEEE 802.3 2012, Clause 33 is describing two alternative schemes for implementing PoE with 10/100 Mbit twisted pair connections

View attachment 124046

See also: https://en.wikipedia.org/wiki/Power_over_Ethernet

Compliant PSE has to check the load condition to avoid damaging standard non-PoE aware equipment, which may involve a common mode short or 75 ohm resistor to ground.

@FvM can i connect the 12v supply in place of PSE circuit and in PD i can collect it with some step down regulator for my own use. is it possible?

 

[D.A.(Tony)Stewart]

When I designed 24 channel PoE rack for AVAYA (nee Lucent) in 2001 ( who were on the PoE Stds committee), they specified unused conductors of a cable. This is referred to as Alternative B where I supplied a polyfuse™ for a 10W peripheral, (such as a Lucent VOIP center on each port) powered from the 1U high rack with a 180W 48V SMPS.

 

[balagbc]

When I designed 24 channel PoE rack for AVAYA (nee Lucent) in 2001 ( who were on the PoE Stds committee), they specified unused conductors of a cable. This is referred to as Alternative B where I supplied a polyfuse™ for a 10W peripheral, (such as a Lucent VOIP center on each port) powered from the 1U high rack with a 180W 48V SMPS.

@SunnySkyguy i ddnt get it. tell me is it possible to transmit 12v supply directly in unused spare cable?

 

[KlausST]

Hi,

It seems you didn't read our answers nor followed the given links. So it's hard for us to help.

* if you want to build your own thing, then do everything you want.

* if you want to keep on PoE standard, you first need to read the documents. Then you see, as previously mentioned, 12V is no PoE standard supply voltage

Please differentiate between connector and signal_transformer.

Klaus

 

[FvM]

As said, you can of course supply 12 V to unused ethernet wires, or through transformer center tap of used pairs, as you like.

If there's a certain risk that regular ethernet equipment is plugged to the port (I think, it always is), then you should design your power supply in a way that it detects this situation and shuts down.

The worst case is a standard non-PoE interface where each pair has a common mode termination with a 75 ohm low power resistor to ground. Supplying 12 V between two pairs can burn the resistors.