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Questions tagged [ethernet]

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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Correct Ethernet Jack + Magnetics for 100Base-TX

I've been shopping around for Ethernet jacks for use in a personal project. The part specifically states that it's internal PHYs are 100BASE-TX/10BASE-T/Te IEEE 802.3 I understand the basic ...
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1answer
49 views

Should Ethernet MDI Pairs all be Length Matched (Inter-Pair) before going into magnetics?

I've been trying to find information for the above question and I can't seem to find anything. I have 1000 BASE-T lines coming from an Ethernet cable to a PCB mounted connector. I'm pretty much ...
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2answers
158 views

Detect activity on RJ45

I would like to make a circuit that allows to detect activity on a RJ45 cable (on which Ethernet would be used). When the cable is only connected to a single computer, link test pusles are emitted. ...
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1answer
208 views

How are 200 GBit/s over twin-axial copper cable achieved?

The 200GBASE-CR4 standard [1] defines ethernet communication with 200 GBit/s using four lanes and PAM4 modulation over a maximum distance of 3 m. A single PAM4 symbol encodes two bits, therefore, I ...
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41 views

Hardware testing for Ethernet

What are the hardware tests for Ethernet? Just need to verify the MII/RMII timing waveform with respect to specifications given in the datasheet.
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2answers
208 views

How does “bidirectional” transmission on gigabit ethernet work 2?

I was looking for an answer to the question how the 1000BASE-T transmission works and I came up with this post How does "bidirectional" transmission on gigabit ethernet work? but still a few ...
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3answers
21k views

How important is the shield on an RJ45 connector?

If I am going to use a PCB mount RJ45 connector for 100mbps Ethernet, does it need to be a shielded connector, or can I get away with using an unshielded one? Is there some standard which deals with ...
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1answer
23 views

GbE Phy(88E1543) with POE+ PSE(LTC4266) design (POE+ magnetics? RJ45 with Integrated magnetics?)

I'm trying to understand how i can inject power to a 4 bank RJ45. I want to use these parts : - LTC 4266 4 ports PSE (802.3 at compliant for GbE, in type1 class3 for 13W at each port) - Marvell ...
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3answers
132 views

how can homeplug device send ethernet down mains wiring

AFAIK when you wire a patch cable out of 5e, you only need to wire two of the conductors correctly for it to function as a ethernet cablebut you won't get gigabit ethernet. However Homeplug uses ...
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1answer
2k views

stm32f207 ethernet interrupts problem

I installed RTX (rtos from Keil) and Ethernet library from STM for stm32f207 MC. I configured UDP using ethernet + LwIP as in examples from STM. Without RTOS UDP works fine. I send and get packets ...
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1answer
109 views

How to get ip address Schneider PLC controller TM218LDAE40DRPHN? [closed]

I am new to PLC technology and I am doing the following step, listed below: Connect from PLC to retrieve data through Ethernet using Modbus TCP/IP. I found that PLC didn't have its IP address ...
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2answers
487 views

Ethernet ground multilayer pcb

I'm currently re-designing a 12-layer pcb. The only thing I am still struggling with is the routing of the ethernet. The layer stackup is as follows: Top Layer GND_1 MidLayer_1 PWR_1 MidLayer_2 ...
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1answer
41 views

Thin CAT6 cable - RFI problems?

I have got a short length (1m) of standard fat CAT5 shielded cable that runs inside a piece of equipment before the signal exits via a bulkhead connector to a PC. It's the old kind that is a real pain ...
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0answers
38 views

stm32F401re ethernet shield unable to associate IP address

I bought STM32 F401RE and Ethernet shield HR911105A with MCU W5100. I'm not able to configure simple connectivity with it. I have setup all SPI wires and simple code for setting up IP, subnet, and ...
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1answer
285 views

Embedded Ethernet Solution w/ PoE+; SPI or MII?

I am currently undertaking my first hardware design attempt of an embedded Ethernet project w/ PoE+. I have experience working with embedded systems with Ethernet (mostly ARM M3/M4 processors with ...
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1answer
56 views

which interface to use TBI, GMII or MII? (FPGA)

I am working with the SoC FPGA Smartfusion2 M2S010-MKR-KIT. It is intended to exchange some data between the SoC and the PC. For that reason, I aim to use Ethernet. As far as I understood, in order ...
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0answers
26 views

Ethernet trace layout and passive placement

I'm designing a board (with KiCAD 5.1.0) besides other I need to properly route two ethernet ports and the whole board should be kept as small as possible (50x82mm). The guidelines of components (...
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2answers
68 views

Single pair ethernet (SPE) PHY with ESP32

can I connect this Single Pair Ethernet PHY http://www.ti.com/product/DP83TC811R-Q1 to a ESP32 chip? Do I miss something? Does anyone already know a Switch for Single Pair Ethernet? Looking forward ...
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1answer
135 views

Gigabit detection DIY

Ethernet up to 100Mbps uses only 2 of the 4 twisted wires in an ethernet cable while gigabit is using all of them. Connecting an LED to one of the gigabit-only pairs should therefore make it easy to ...
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2answers
3k views

PC start button effect from electrical point of view

What I basically want to do is to connect one of the digital pins of a network-attached Raspberry PI to (one of) the connectors of the PC Power On button, so that when I issue a command coming on the ...
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1answer
62 views

Special requirements 100Mbps (Ethernet) connection to PCB

Is there any special requirements/limitations to how 100Mbps Ethernet conductors can be connected to the PCB? For instance in the design prompting the question I have a Ethernet connection entering ...
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1answer
38 views

What is the maximum routing distance between MAC to PHY recommended?

Picture to Keep the Terminology Clear I am in the plan of using ETH for inter processor communication I need few ETH lanes to be shared between boards, i wish to avoid ETH PHY and magnetics as the ...
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0answers
48 views

PHY Link only establishing 10 Mbps speed when both devices 100 Mbps capable

I've designed a circuit board with a Microchip switch (KSZ9897) going to a Ethernet-to-VDSL module (LX200V20). The PHY ports between the two devices are connected using a transformerless connection ...
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1answer
319 views

Should I terminate the MII/RMII interfaces?

For Ethernet PHY design, the MDI interface should be terminated. Then how about the MII/RMII or GMII/RGMII interfaces? I've seen some designs terminated them, and most not. There are some PHY chips ...
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4answers
109 views

Can you replace a RJ45 connector with smaller connector?

I'm designing a small board that needs an ethernet connection. However, the RJ45 jack takes considerable space. I would like to reduce the footprint of the connector to safe some space. Would it be ...
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1answer
55 views

Why this evaluation board use different track impedance than the right one? Ethernet PHY, routing

Im doing a design with a implementation of 1Gb ethernet switch, for that I bought a evaluation board to do it well. The problem is that in the layout of the ev board I can check that the track ...
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1answer
108 views

mbed OS 5 TCP Socket

I have a few question regarding mbed OS 5's new TCP API: Some background: I will have multiple mbeds linked via Ethernet to a PC. The PC, whose IP address is fixed and known by each mbed, initiates ...
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3answers
61 views

IP Camera and USB data transmission over Ethernet Cable

Currently I am working on a project that requires connection of the Arduino and IP Camera over single Ethernet cable to a laptop and additionally supply power to a robot. The goal is to stream Video ...
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1answer
39 views

Add Ethernet Switch chip to project based on PIC18F97J60

We developed an Ethernet-connected device that uses the Microchip PIC18F97J60 controller. This particular PIC contains the PHY that allows us to simply connect the chip to Ethernet magnetics and then ...
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1answer
34 views

enc28j60 ordere wrong resistors

i prototype a small board with ENC28j60. Instead of 49.9 resistors I have ordered by mistake 47R ones, What do you think? will it work? It is only 10M ethernet
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3answers
2k 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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3answers
877 views

Connecting TVS before or behind Ethernet transformer?

I looked at several designs and recomendations. Why do TVS diodes sometimes connect before and behind transformer? What are the pros and cons of connecting before or behind?
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1answer
25 views

100BASE-TX (MLT-3) to 100BASE-FX (NRZ-I) conversion

Is there a way to convert 100BASE-TX packet to 100BASE-FX packet only by use of MLT-3 to NRZ-I coding scheme convertion by means of simple logic ICs such as some trigger ICs (wichout the use of FPGA ...
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1answer
384 views

SGMII, MDIO and link training

I am reading this document : https://www.nxp.com/webapp/Download?colCode=AN3869 I got this link from NXP support, but I did not get a precise answer to my questiosn and I would like to be sure : The ...
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1answer
681 views

How can I configure PHY in cubeMX on own board?

I made a customboard using STM32f217VET microcontroller and KSZ8081 PHY (builtin pull-up resistors for TXP TXM and RXP RXM). I Configured my board to use MII mode, anda I used a 25MHz oscillator to do ...
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1answer
3k views

Picotux alternatives available? [closed]

I wanted to use a tiny Linux computer to read data from I²C bus. I knew there was Picotux, and I was thingking about buying one. But the website is down, so I guess there's no Picotux anymore. :( ...
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1answer
100 views

Adding fiber optic ethernet to a circuit

I'm working on a project that involves transmitting data over very long distances (10-25km) where radio communication is unavailable, and I have been looking into the possibility of adding a fiber ...
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3answers
814 views

How much mains leakage does an Ethernet connection to a PC induce, and what is the operating leakage path?

It seems that some users on another Stack have reported GFCI nuisance trips caused by mains leakage through twisted-pair Ethernet cables connected between computers on different branch circuits, or ...
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2answers
153 views

TVS diodes for Ethernet/PoE?

I am getting confused in selecting TVS diode for Ethernet Interface. Should I connect one bidirectional TVS diode across a ...
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1answer
52 views

Gen3 LAN Bypass

I am working on LAN Bypass circuit for 1000 Mb/s Ethernet ports. I need to use relays to turn the bypass mode or no link mode on during power failure. My doubt is whether the relays should be used ...
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1answer
54 views

Structure of Pairs inside a Cat Cable

Is there a standard arrangement for the pairs inside a Cat7|6|5 Ethernet Cable? As shown in the picture, they are in the sequence Orange-Green-Brown-Blue, or the Orange Brown always as opposite pairs,...
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1answer
59 views

Ethernet connection using only one twisted pair

For my degree work, i make some reseaches for different bus systems and i've found ethernet a bit different than others: The old 10Base5 and 10Base2 ethernet used only one pair of conductor to ...
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1answer
120 views

1000BASE-T MDI Return Loss Measurement

IEEE 802.3's clause 40.8.3.1 specifies a certain a MDI return loss. The specification states that this return loss shall be maintained at all times when the PHY is transmitting data or control symbols....
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1answer
38 views

how to confirm that PCB Ethernet layout does not affect perfornace

short version: - How to test if ethernet traces on PCB causing any distortions to the signal? - Is it possible to generate ethernet signals from a windows computer and measure them with an ...
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1answer
100 views

Ethernet transformer differences

Good morning, I have a design using these magnetics over here to filter and isolate the ethernet signal: https://www.mouser.com/ds/2/336/-515468.pdf And I have this other component as an alternative:...
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1answer
82 views

STM32F103 reset button does not work [closed]

I am working project, using STM32F103C8T6 and W5500 Ethernet module. My project is something like network relay. My problem is ...
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4answers
1k views

What is needed to go from single Ethernet to many?

I have an embedded Linux system with a single Ethernet port, but I need to go to many ports. It is obvious I need to add magnetics and ports. The trickier parts follow. My processor has an on-board ...
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1answer
53 views

Transmission distance rs485 vs ethernet

I have a question, why is rs485 limited to less than 100 meters at 10mpbs ( mbaud ) and is 100Base-TX ethernet applicable on 100 meters with 100 mbps bitrate i know that rs485 normally use a sort ...
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3answers
95 views

Power small microcontroller from motherboard RJ45 ethernet port

I'm wondering if it's possible to power a microcontroller (e.g. ATmega328) from a Ethernet RJ45 motherboard port. Unlike USB, there is no power line, all pins/lines seem to be data only. I am ...