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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Determining how much current I can actually run through my Cat6 24AWG Cables in my confirguration?

I want to use a CAT6 (24AWG) RJ45 cable to carry a total of 2A at 48V. As per the AWG Chart, I see that the Maximum amps for power transmission is 0.577A but the <...
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328 views

Explanation of ethernet transformer signals RDCT, TDCT, RXCT, TXCT

I have seen in a schematic that the RXCT and TXCT are connected to Ground but actually there is no connected no ground to the PCB: Can anyone explain to me what do these signals mean and if it is a ...
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286 views

Internal physical layer in microcontrollers

I am working on a project and while doing the component selection I realised that many microcontrollers have MAC & PHY layer on the different chip. Except for TM4C1294 microcontroller (there might ...
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366 views

is MDIO required for PHY?

Most of the Ethernet PHY chips (e.g. LAN8720) provide strapping option to control operation. I am short of IO pins in my uC, and I do not need (AFAIK) to change anything more in the PHY operation. (...
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110 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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Ethernet RMII on two layer PCB

INTRODUCTION: I'm aiming to design an Ethernet connected system as a hobby ( ie. plenty of time but not wishing to spend much ). My design constraints would ideally be sticking to a 2 layer 100mm x ...
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206 views

ATmega communication with I2C + extender or with ENC28J60 ethernet module?

I want to communicate between ATmega328P µC's over 'long distance'. The ATmega µC's will be 5m to 20m apart and the total length of the chain will be around 50m with up to 10 ATmega's in one chain. ...
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1answer
207 views

Simple measuring Ethernet throughput

I have STM3220G-EVAL board (STM32F207IG MCU). I'd like to measure (approximately) its actual Ethernet throughput (board <-> Windows PC). I have CubeMX sources. There are several examples (TCP, ...
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33 views

Ways to connect Arduino / Microcontroller to the Web? [closed]

What are the best ways to connect an Arduino or a microcontroller (PIC...) to Internet/Web. I would like to be able to send and recieve information from the Arduino/PIC to the Web and vice-verse even ...
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132 views

Ethernet mechanical switch for testing [closed]

We have an application which accepts streams over IP and displays it on the LCD Screen. We want to test the Ethernet plug-in/Plug-out test. Do you know any IC which can simulate someone plugging in ...
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395 views

Gigabit Ethernet switch unused RGMII/MII/RMII interface

I am working on 5-port gigabit Ethernet switch based on Microchip KSZ9897. As the KSZ9897 is 7-port gigabit Ethernet switch (5 x 1000BASE-T/100BASE-TX/10BASE-Te IEEE 802.3 + 2 x RGMII/MII/RMI) and I ...
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101 views

Do waterproof RJ45 connectors with integrated magnetics exist?

I've been searching for days and can't seem to find a rugged RJ-45 Ethernet connector with integrated magnetics. Probably it would be good enough if the connector was just potted so water cannot leak ...
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166 views

mbed Socket Thread

I need to establish an ethernet connection between a host and mbed, where the host can send commands to the mbed (e.g. move forward, move backwards, stop, etc). As there is no telling when these ...
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1answer
55 views

convert from serial modbus to ethernet through plc?

can I use a plc as a converter to convert from serial modbus(RS485) to either ethernet or usb using code ? , the plc is modicon m340 without communication module but the cpu has serial port , ethernet ...
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920 views

Ethernet magnetics - PHY side center tap isolation

I am designing a PCB that will use a Microchip KSZ9896C 6-port Gigabit Ethernet Switch. In the datasheet (section 7.2) they state that : "the four transformer center tap pins on the KSZ9896C chip ...
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1answer
532 views

Center tap of transformer for Ethernet interface

When you see Ethernet PHY chips' application circuit, you can find out the difference about connecting center tap of transformer. Some PHYs should be connect to the DC power but some don't connect to ...
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861 views

LAN port tester

Is there any way to make a simple LAN port tester that can plug into an ethernet port and check for connectivity. I dont want to use the cable testers as it require both ends of a cable to be plugged ...
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1answer
533 views

Are there any special internal Ethernet connectors other than RJ45?

I am working on the board that suppose to have 1 GbE port (10/100/1000BASE-T). Looking at connectors all I seem to find is standard RJ45 connector. However in my design the board itself is not ...
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RJ45 jack with 8 and 10 pin difference

I need to use the next Ethernet interface design which it's got a RJ45 10 pin, the schematic looks like this: (The RJ45 datasheet is: https://katalog.we-online.de/pbs/datasheet/7499111446.pdf) (PHY ...
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106 views

Direct connection between two SFP+ cables [closed]

I have been reading a lot about modern fiber networking recently and I have a clarifying semi-hypothetical question: Imagine I have two 3-foot sections of Multi Mode Fiber, and four SFP+ 10G ...
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961 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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402 views

Ethernet Interface PCB layout

So based on the responses from this thread: Ethernet Interface PCB layout requirement (if any) I made an Ethernet interface layout the best I possibly could using 2 layers. The circuit is of the ...
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949 views

high speed microcontroller - pc communication

I have a project where I have to sample a 4 bit bus every 100ns continuously for a data logging application (I need very low sampling jitter as well). I have a uC that can go up to 300MHz so speed isn'...
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362 views

Pushing 50W over PoE?

I'm wondering if it's possible to drive 50W via PoE (cat 6e or cat 7) single cable? I want to power up a quite hungry ARM board, which has power rating of 5V 3A (15W) and a camera, which needs 12V 2....
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557 views

Powering a 2amp micro-usb device over cat5

There was once a phone in my bathroom, so now there is an LV box with a Cat5 cable in it at the end of a 30ft run. Can I hack something together to power a Google Home Mini with that cable?
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344 views

LAN8710A on STM32

I am working on a project in which I want to have an STM32 running FreeRTOS lwIP. I want to connect it via the MII instead of the RMII configuration. I have studied the datasheet for LAN8710A and I ...
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3answers
662 views

Packet loss on LAN point-to-point

I would like to ask if packet loss in p2p LAN is a normal behavior in LAN. And now in more details: I am connecting PC to target board with TI's chip and LAN9221 controller. I am doing a ping-pong ...
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1answer
343 views

Splitting a cat 6 cable through wire/cable connectors

There's been a cock-up in the internet wiring at a building I'm helping out at (I'm installing the networking there) and the builder has tried to rectify the situation with a solution I have zero ...
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1answer
173 views

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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392 views

Ethernet Interface PCB layout requirement (if any)

I am doing Ethernet communication to/from an MCU. I got it working great with an ENC28J60 development module: https://www.digikey.com/product-detail/en/olimex-ltd/ENC28J60-H/1188-1044-ND/3471433 I ...
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158 views

Ethernet Transceiver Chip 100ohms impedance

I've designed a pcb which has a 10/100/1000 Mbps Ethernet Transceiver. It's been already manufactured and I am now testing it. I don't have much experience with electronic design therefore I didn't ...
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1answer
459 views

LAN9500AI (USB to Ethernet IC) hang if Ethernet cable removed

I need some help on debugging the issue faced on USB to Ethernet design. I have took reference form LAN9500Ai Development board. Issue:- When Turn on the Power , USB to Ethernet work, and Three LED ...
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1answer
100 views

Circuit design for co-layout the XTAL and CPU clock output

I got a circuit design problem. There is a ethernet switch in my circuit. It is needed 25Mhz crystal input. There are two option, 1). Using external crystal. 2). Using CPU clock output. Its block ...
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72 views

Firmware update and data exchange using ethernet

I use PIC18F97J60 because its built in ethernet controller to exchange data via lan cable. I want to update the firmware of the mcu using the same controller which means using bootloader for the ...
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1answer
149 views

Off board Ethernet connector

I have to design a PCB board for a project where I need to add Ethernet connectivity (100Mbps) which only will be used during the setup process (it won't be connected all the time). The problem is ...
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1answer
305 views

Detecting disconnected ethernet cable

I want to detect if an ethernet cable has become disconnected using an Arduino. The Arduino will be plugged into a wall, not battery powered. Using a LM358 seemed like the correct fit. I hooked up ...
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1answer
399 views

Isolation Voltage rating of Ethernet Magnetics

I am at the front end of a project that, in part, measures Industrial Voltage levels: 208 Vac through 600 Vac, 3 phase. This device needs wired Ethernet connectivity. I've got lots of options for ...
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2answers
2k views

Which RJ45 pins should I use for power supply?

I'm somewhere in a process of creating mini automation system for hobby use. I've already put CAT 5e cables with RJ-45 connectors in walls. They are somewhere between 5 - 30 meters long. On one side ...
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1answer
187 views

POE power will not interfering on Data travelling on Ethernet , Whats the logic

I was design POE+ circuit , so I read lot of articles on POE(power over Ethernet) IEEE802.af 15.4W on PSE side , For 10/100 base T can use Alternative A method where it use to deliverer power on data ...
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2answers
3k views

Differential Pair Length Matching for DP83848I

I'm looking in the datasheet and layout guide of the DP838481 but I can't seem to find where it talks about length matching for the RX and TX differential pairs. It only mentions length matching for ...
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1answer
96 views

Power over Ethernet identification error?

I have a custom board which is powered by Ethernet and I am using the LT4275B from Linear using the recommended schematic. When I am using a cable with only the data pairs [1-2]&[3-6] ([4-5]&[...
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3answers
323 views

Are RJ45 jack sockets universal regarding CAT-X cables

I've noticed some trade/wholesale websites list CAT-X jack sockets separately as the individual numerical version, i.e., (CAT-3 jack socket). I'm aware CAT is a standard, and RJ45 is the socket ...
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0answers
509 views

Is this a suitable common mode choke?

I've got a system here where I get 12V DC from a laptop charger which is connected to the wall. That 12V gets stepped down to 5V using the TPS56221 buck converter (running this at 500 kHz, with an ...
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2answers
1k views

Using Cat5 for DSL from NID - good idea to double up wires for signal integrity / strength?

I am doing some rewiring of our internal phone lines (almost entirely removal of unused lines). The issues we have run into is the router will every now and then simply not connect from the house to ...
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1answer
547 views

CRC implementation for ethernet

With an example for data with a hexadecimal value of 0xda and a polynomial 0x07, I would find the CRC as follows (using the ...
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1answer
153 views

What is the use of CLK125 on Ethernet PHY?

We are working on a KSZ9031 Ethernet PHY with a Zynq 7020. I don't know where connect the CLK125 signal on a Zynq 7020. What is the use of this signal ? Thanks, Jeff
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157 views

nxp microprocessor ethernet socket coding and sending code [closed]

I have nxp lpc43s50 microprocessor and I made an ethernet connection via lan8710 and at24c02 .I know how to connect at24c02 to my microprocessor pins .However I don't know how to send codes to my ...
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2answers
465 views

RJ45 dual LED green and yellow operating

Attached is a small section of USB to Ethernet converter design. RJ 45 Connector has one dual LED (see attached) Green and Yellow, backward connected, and drive via the LAN9500 chip pin27. As per ...
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87 views

usage of at24c02 eeprom with ethernet module

ı design a altium circuit schematic which consists of lan8720 tranciever rj45 and also at24c02 eeprom .However ı dont know exactly what MAC means and what it does. Why do we use eeprom with ethernet?...
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1answer
107 views

ethernet connection of nxp processor [closed]

ı designed a circuit schematic by using altium designer to ethernet connection of my processor (nxp lpc43s50fet256) ı added a circuit schematic as altium designer file .You can see my complete ...