---
title: "W5500 POE and/or 4 Wire"
url: "https://maker.wiznet.io/forum/9709"
markdown_url: "https://maker.wiznet.io/forum/9709/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "tk4cam"
created: "2013-11-28T15:52:31+09:00"
last_activity: "2017-05-04T08:30:33+09:00"
language: "en"
views: 542
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 POE and/or 4 Wire

## Question

Asked by tk4cam on 2013-11-28 in Ethernet Chips.

Hi Wiznet Team,

i currently create a Test PCB with a W5500.

One Question: On the Datasheet w5500_ref_0901.pdf
Right down Corner the resistor Network 49R9 on PIN4+5 / PIN7+8

it is necessary to connect a Cable on this PIN’s or can i use a 4 Wire network cable.
and it it necessary to use the resistor network without 4 pin wire ???

please Info

Thomas

## Replies

### Reply 1 by peter, 2013-11-29

It is not necessary. But, We recommend to use like our reference.
The unused pairs(4-5, 7-8) with 49.9ohms are connected to the chassis ground(CGND) with a high voltage capacitor(4.7nF/2kV). Any ESD high voltage entering on these pairs will pass to chassis ground(CGND) without damaging the circuit or the device.

Thanks

---

Source: https://maker.wiznet.io/forum/9709