Questions about the electrical implementation of Ethernet; ask another Stack Exchange for software or protocol questions. Specify the speed as 10/100BASE-T is somewhat different from 1000BASE-T, apart form the speed. Those are copper standards; Ethernet over fiber optical cable is also defined.

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ENC28J60 connected to Arduino on SPI

I have an Arduino Uno, that has been connected using SPI to an RC522 rfid board and an ENC28J60 ethernet board. SS1 for ethernet is port 8, and SS2 for RC522 is port 10. I can use the RC522 without ...
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Broadcast traffic issue in PLC Ethernet network

The setting: network with about 10 PCs and 8 AB RSLogix 5000 PLCs. The issue: Everything is communicating OK, but I'm seeing what appears to be a lot of broadcast traffic within the network. It is ...
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43 views

Sending Serial Data over Ethernet Using C# [closed]

I need to send some serial logging data from a laptop to a server (both Windows machines). I was planning to use the Ethernet port to send the data, as sending data over the USB port appears ...
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3answers
187 views

How to Connect USB/Ethernet Shields to Chassis or Digital Grounds

I have a PCB with a few USB and RJ-45 Ethernet connectors on one side. I'm quite confused as to how exactly I'm supposed to be hooking up the SHIELD pins on them though. This is for a host device ...
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1answer
41 views

Adding Wi-Fi to a TCP/IP application that is already running with Ethernet

What to do if you have an Ethernet application that is already up and running with TCP/IP functionality and now you want to add Wi-Fi. Most of the Wi-Fi modules available have embedded TCP/IP stacks ...
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2answers
49 views

Put firewall hardware with ethernet ports between serial ports

I want to put a firewall hardware product between a RTU and PLC to block some Modbus function codes (e.g. write coil, read coil). (This firewall product is able to do deep packet inspection on Modbus ...
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26 views

Which way do the wires go on the ethernet cable? [migrated]

I have already asked this about usb, which is "Which way do the white and green wires go on a usb cable" or something like that. I got the answer "The signals go both ways". I have the same question ...
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0answers
41 views

Would you use Wiznet W5x00 in a commercial product? [closed]

I am working on a project where the product needs to be connected to the local network. For the products we use Atmel controllers (AVRs and ARMs). I choose Wiznet W5100 to be used in the prototype, ...
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40 views

find other end of ethernet cable [migrated]

My house is wired for Cat5e. In each room there is a blank socket with a cat5e cable behind it. I presume they all terminate in a common location. I've looked in all the usual and unusual locations ...
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5 views

W5100 Ethernet shield DHCP fails with a Switch [migrated]

we are using Arduino W5100 Ethernet shield. The code is to try DHCP first and if that fails, then try the static IP. we do the Ethernet Initialization and stop every time. The library is Arduino ...
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24 views

Issues in schematic of Microchip LAN8720 & waveshare LAN8720?

For a project I need to integrate Ethernet with PIC32MX795F512L. For this I had two choices. I thought of purchasing this Waveshare LAN8720 module and directly ...
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2answers
57 views

Ethernet surge and protection

I recently worked with a client who experienced a transient on their Ethernet cabling. As you can see, no actual PCs were damaged, only the Ethernet cards of some machines. We don't know where the ...
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2answers
114 views

House wide automation network: CAN or Ethernet?

I am half-way through building my home automation system. As an electronic engineer/software developer a lot of this has been rolled myself from scratch and I will hopefully be starting to blog more ...
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1answer
70 views

May RJ45 connector with magnetics connected in series?

I have a dev board with a RJ45 connector which has magnetics integrated. I need put it into a case and mount another RJ45 on the panel, sadly I have only another connector which also integrate the ...
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1answer
48 views

Does the 802.3 Ethernet standard provide a recommended circuit design?

I have a project I am designing whose fundamental parts consist of sensors connected to a micro-controller. the micro-controller will then send the data out over an ethernet port using standard tcp/ip ...
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1answer
31 views

ethernet socket interface throught nail bed

I need to make a test nail bed for a board that has an Ethernet interface: in the bottom of the board there is access to the socket ethernet pins i could place test nails under the ethernet socket ...
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3answers
100 views

ENC28j60 ethernet interfacing with PIC18F4520 help needed

I am a newbie to ethernet controller. I need to use ethernet controller to send sensor data to our server using http get method. I went through ENC28j60 documentation and microchip's TCP/IP stack as ...
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2answers
61 views

Control door with RS232 or Ethernet relay

Our company use a fail safe electric bolt with a remote control for the entry door. It closes when the power is ON and vice versa. It does work normally but I want to make a hot button for the ...
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4answers
160 views

Can I use an ethernet module (or an USB connection) for light communication? [closed]

I'd like to transmit data (e.g. copy a file between two computers) at high speed via light. I found lots of examples around the web but mostly the speed is really slow because a serial connection ...
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2answers
140 views

Why didn't 1000BASE-TX gain more popularity than 1000BASE-T?

1000BASE-T uses all 8 wires in a twisted pair to both RX and TX at the same time. It does it using (what seems to me) a complicated process known as echo cancellation. Details here. 1000BASE-TX ...
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1answer
87 views

Ethernet switch controller chip

Recently I bought an ethernet switch controller based on the Realtek RTL8305NB chip. It was bought as a proof of concept for my robot. Unfortunately, the board is too big and I want to design my own ...
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3answers
72 views

How is a Twisted Pair's +-2.5v used to send a 1 or a 0?

This is a multi-part question that I'm asking as a follow on to this answer from my other question. I know 100BASE-TX transmits through a pair of wires, that are twisted around each other so that the ...
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7answers
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What if there are an odd number of twists in a twisted pair cable?

I am not an electrician, or a student of the field. I am a Network Engineer with a curiosity bug and that has recently taken me to exploring cabling and Twisted Pair specifically. I say this to plead ...
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1answer
85 views

How to create Simple Web Server with Mbed and W5100 Ethernet Shield

I'm trying to develop a simple web server application with Nucleo f411re and w5100 Ethernet shield. My question is why the client.is_fin_received() function always returns 0. Why doesn't my web page ...
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1answer
44 views

Differential POE 1000base-t signaling through analog multiplexer

I want to make a test device which can route network inputs to one output. For example it could sit between two computers and a network switch. The TS3L301 looks promising, but I am unclear about the ...
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1answer
68 views

MAC PHY defenitions

from Wikipedia: The media-independent interface (MII) was originally defined as a standard interface used to connect a Fast Ethernet (i.e., 100 Mbit/s) media access control (MAC) block to a ...
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47 views

can i interface profinet protocol to ethernet interface?

i have a profinet device and an Ethernet port which is dedicated for KNX protocol. can i connect my profinet device to this Ethernet port?
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1answer
57 views

Ethernet PHY Layer Compatibility

I have two different embedded devices with ethernet connection. One is based on Texas Intruments DM648 DSP chip and the internals of the other are unknown to me. When I connect each one of them ...
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1answer
144 views

How often are bits sent over cat 5 ethernet cables?

sorry if this is a bit of a dumb question, but I read somewhere that cat-5 is 4 twisted pairs. so that means at most it's transmitting 4 bits at a time. What determines how often the 4 bits are ...
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2answers
54 views

Why use a custom module instead of a clock divider?

Background I have created a VHDL module that continuously generates a one-bit wide pattern of "1010101010..." as long as it's enable bit input is asserted high, as part of a class assignment. In the ...
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2answers
52 views

Why use a multiplexer the select from GND and VCC instead of an Inverter?

I have created a VHDL module that generates a one-bit wide pattern of "1010101010..." continuously, as long as an input signal called "start" is asserted high. This is the elaborated circuit design ...
2
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1answer
63 views

Ethernet RX and TX connections

Is there some standard how the RX and TX cable pairs in a device are connected to a RJ45 ethernet jack? Clearly I cannot just connect the TX pair of device A with the TX pair of device B. That would ...
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3answers
75 views

Adding ethernet ports - increase in gbps

I was wondering how this would scale. If you have one ethernet port on a device and it can handle 1 Gb/s - let's say - it can handle 1 Gb of data each second, right? But if you add more ethernet ...
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1answer
122 views

Auto-negotiation and link training in 10GBASE-R standards family

I'm selecting PHY IP core for our future chip supporting 10G ethernet. I have some confusion regarding which 10GBASE-*R standards have auto-negotiation and link training features. 10GBASE-KR, which ...
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1answer
61 views

Differences and conversion between encoding techniques (NRZI, Manchester, MLT3)

I'm currently reading a lot about different encoding techniques for data transmission, in particular ethernet, fiber (and usb). 10Base Tx ethernet uses Manchester encoding for data transmission. But ...
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2answers
74 views

Ethernet Connector(MAG JACK) question

I am curious about why there are wings attached to the magjack for the Ethernet. Other RJ45 jacks without magnetic don't have the wings, but most RJ45 jacks with magnetics inside have them.
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3answers
122 views

FPGA TCP Connection

Is it possible to have a TCP connection with an FPGA? I need a low power device that can control relays based on Ethernet packets that are received and send back confirmation packets.
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2answers
117 views

Is it possible to remap/change the pins of an IC?

I was wondering if it would be possible to change the a pin of a microcontroller to another pin. Does it depend on the chip or is it generally (im)possible? Specifically, I'm interested in Ethernet ...
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1answer
107 views

Reverse MII and TXER, RXER pins

I've got two ethernet ICs that should be put back to back with reverse MII mode. For this, I should cross the TX and RX pins and the application note of the reverse MII chip says, the TXER and RXER ...
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1answer
60 views

Unused Ethernet pins

I want to use the LAN9500AI controller in an application. This is a USB <-> Ethernet bridge with access to the MII interface. Since I just need the USB and MII interface, the ethernet interface ...
3
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1answer
130 views

Ethernet LED & Diffpair Clearance

How do you maintain creepage distance between diff pairs and the LED terminals on an Ethernet connector? My understanding is that based on EN60950, for 250V IT equipment, the air clearance is 2mm and ...
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0answers
69 views

Ethernet: Client implementation on Arm controller using lwip

When implementing a client for communication over Ethernet, what is the best way to use raw API (from the lwip stack)? Details and Contraints: 1. Controller Architecture - ARM (from TI) 2. RTOS is ...
2
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1answer
179 views

Chassis ground on Ethernet RJ45 Connector

In the reference schematic of an Ethernet transceiver, I noticed that the chassis ground is connected to system GND by 1nF/2kV Capacktor(C24). What is the purpose of doing this? The ...
2
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1answer
71 views

EMP Protection of Ethernet Lines

I'm currently working on protecting 1000Base-T Ethernet lines from EMP using filter connectors such as described on page A-7 of this doc: ...
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1answer
90 views

Termination of unused PoE pairs

How important are the specific termination values used for PoE pairs (pins 4&5, 7&8)? Below is the recommended Ethernet front end for Micrel’s KSZ8841/42. ...
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2answers
132 views

How do Ethernet cables/USB cables send binary 0?

I was wondering how your computer sends binary zero as an electrical signal. Is there a certain delay or does it do something unique.
0
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1answer
98 views

What's the advantage of PAM modulation over QAM?

What are the main advantages of PAM (Pulse amplitude modulation) modulation over QAM ? Ethernet is using PAM for 1000BASET and 10GBASET, but any other high speed links use QAM like DOCSIS, ADSL/VDSL ...
2
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1answer
36 views

How to synchronize random resets in two Ethernet Controllers (DP83816)?

I use two Ethernet Controllers (DP83816) in a design which also has a CPLD. When the power is supplied, Ethernet chip undergoes a random reset and it resets the CPLD (XC95144XL) internally. Since I ...
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4answers
136 views

A low cost method to perform Eye-Pattern Testing on 100 MBit and 1 Gigabit Ethernet Transceivers

I'm looking for a low cost method to perform Eye Pattern Testing on 100MBit and 1 Gigabit Ethernet transceivers. I do not own a BERT and I have a 4 channel 500MHz DSO available.
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1answer
194 views

Why is Cat5/Cat5e Ethernet cable rated 100MHz?

As the questions says, is there any specific reason why Ethernet cable is rated 100MHz? For a 100Mbps Ethernet the data rate is 100Mbps, and the baud rate is 125Mbaud, because of the specific line ...