Ethernet Surge Protector

[tantudaisu]

Hi,

I need to design an Ethernet Surge Protector. I have fond one simple and cheep circuit solution on the web:
https://tyconpower.com/products/files/TP-ESP-100-POE_Surge_Protector_Spec_Sheet.pdf

Can anyone advise how to select varistor Z1 and Z2? Why they are different?
Some diodes i.e. D1 and D7 are connected in parallel. Can anybody explain why?

- tantudaisu -

 

[westom]

Can anyone advise how to select varistor Z1 and Z2? Why they are different?

View the various functions. Some are TX and RX. Low voltage. Other wires are voltage for POE. Typically greater than 48 volts.