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.

learn more… | top users | synonyms

-5
votes
0answers
67 views

How does a CAT5 Ethernet cable work? [closed]

I can't find many resources online that go over this. I'm curious how a digital signal is transmitted over Ethernet and how the other computer can interpret it.
1
vote
1answer
21 views

How to flash DM9000CEP V5 board

I am really new to the world of building hardware and software electronic devices and need help with a situation. First off let me give a brief background on what I know about electronics and ...
1
vote
1answer
53 views

Connecting Transformer to Ethernet PHY

I have Ethernet PHY from Marvell (88E1111-B2-BAB1I000) and Ethernet transformer (S558-5999-AT-F). By mistake the MDI P&N connection got interchanged on the transformer side. Will it work?
0
votes
0answers
15 views

Insertion loss requirements for 100BASE-TX

I'm evaluation an insertion loss measurement of a transmission line for 100BASE-TX and have turned to the specified requirements in the IEEE Std 802.3-2012 for guidance. There I stumbled over ...
0
votes
0answers
38 views

backplane for power etherner, rs232 amd rs485?

I’m trying to build a midterm system between a costly and highly custom VPX and a platform where each board interfaces with one another by cables. for example: imagine I have an off the shelf mini-itx ...
1
vote
2answers
80 views

RGMII and RMII backwards compatibility

According to Wikipedia: GMII [...] is backwards compatible with the media-independent interface (MII) But is RGMII backwards compatible with RMII? I'm asking this because I'm making a ...
0
votes
0answers
35 views

How to trigger a sampling oscilloscope on a PAM-5 signal

I am trying to acquire an eye diagram on a Gigabit Ethernet (PAM-5) signal, measuring differentially over pair 1. I am using a Tektronix DSA 71254c. I have not been able to successfully configure the ...
2
votes
1answer
48 views

How to connect GND between both sides of a signal transformer

I am doing a test board to learn more about ethernet, differential pairs, etc. I understand that the transformer will isolate my board from the world. But I wonder how to design the termination ...
1
vote
1answer
44 views

Atmega168 and ENC28j60 - Unable to communicate

I would like to make a web server from an AVR uC. I use Atmega168 with the ENC28J60 ethernet module. I have connected the module with my Atmega using SPI. I have a problem, because the communication ...
1
vote
1answer
44 views

Ethernet driver Circuit

I've been working on Ethernet schematics, i noticed a network of capacitor and resistors present outside the RJ45 connector. For what reasons these passive components are used? I've attached the ...
0
votes
1answer
56 views

How much amps (maximum) are flowing through 1000Base-T Ethernet? [duplicate]

How much amps (maximum) would be flowing through a 5 meter Cat 5/6 Ethernet cable with 1000Base-T speed (IEEE 802.3ab, 5-PAM coding, so voltage levels vary between +- 2V, 1V, 0V)?
0
votes
2answers
88 views

Raspberry Pi controlled power on/off switching of an Ethernet connection

I want to power on/off an (Gigabit) Ethernet connection physically by using some circuit. The main idea was to use a transistor with the Raspberry Pi GPIO to switch an Ethernet cable. The schematics ...
0
votes
0answers
39 views

lwIP initialization hangs when configuring TEMAC

I am working on a my master thesis, designing an FPGA solution, and have run into a very resilient problem. I will try to provide as much information as possible, in the hopes that someone might have ...
-1
votes
1answer
34 views

Converted from ms per int to Hertz [closed]

I am trying to convert from ms per int to Hertz. I have found that my system takes 0.2313ms to transfer one 32 bit interger. Based on this answer Difference between Hz and bps I have divided my ...
3
votes
1answer
59 views

Is my Bob Smith termination valid for Ethernet 100Mb/s?

This is my first ethernet circuit, and I am a noob in differential signal lines. That is why I want to learn with a "simple" circuit. I use the reference schematics from the LAN9512 usb to ethernet ...
0
votes
2answers
96 views

Sending PWM signals down cat5 cable

I working on an LED lighting project where I will be installing 20 boxes in a space, each containing 4 LEDs (RGB and IR.) I want to connect all of these boxes to central board which will drive all of ...
1
vote
1answer
71 views

Problem with Ethernet controller ENC424J600

I have recently produced a number of prototypes using the Microchip ENC424J600 Ethernet IC. I can't a full circuit diagram as this is a commercial product but I have reproduced the relevant part of ...
1
vote
1answer
30 views

In PoE: is alternative A compatible to all PDs?

I am currently designing a PoE plus device. I'm using 1G speed and currently following alternative A configuration (data pairs 1/2 and 3/6). Question is: Can all Powered Devices (PD) support ...
1
vote
3answers
87 views

What can cause an oscillator output voltage to go higher than expected?

I am currently testing a 50MHz 3.3V CMOS oscillator in my circuit, which is connected to two pins/loads - MCU pin and Ethernet PHY pin. The oscillator is rated for 15pF output load, which I could be ...
1
vote
1answer
83 views

Transparent Wi-Fi module with RMII input

I need to convert a Ethernet-connected embedded project with wireless connection. I'm looking for a low-cost (main constraint, less than USD $15) and most open-source/-hardware possible Wi-Fi bridge ...
1
vote
1answer
94 views

How many pairs of wire to use for Power over Ethernet?

I have a custom setup to supply power over Ethernet cables. I used a pair to connect to a telephone and another pair for power. The device needs 12 Volts at 0.5Amps to run. In normal setups, which ...
1
vote
1answer
125 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 ...
-1
votes
1answer
72 views

SFP vs LAN port [closed]

From a board design standpoint, What are the categories to consider when picking between an SFP and LAN port. This is to be used as a 1GE management data path so regarding data rates both options ...
2
votes
1answer
364 views

Using Ethernet cables cable for sensor wiring

I'm exploring the pitfalls of using an Ethernet cable for extending sensor cabling. The term Ethernet cable is used ambiguously on purpose to denote an "easily available 8-wire cable whose category ...
1
vote
1answer
86 views

RJ45 color code for cable with non-standard colors of T568D

I have a UTP cable with the colors: white-yellow, white-black, white-red and white-purple. I would like to use this cable as an Ethernet cable. I know the color code to make straight through Ethernet ...
1
vote
1answer
43 views

Requirements on dielectric strength and isolation between the conductors in an Ethernet transmission line with PoE

I am trying to find out what the requirements are on dielectric strength and isolation between the conductors in a Gigabit Ethernet transmission line. A first place to look would of course be the TIA-...
-1
votes
1answer
74 views

Can a same phy be used for IPV6 and IPV4?

Currently I am using LAN8720 from microchip in my device for IPV4 network?Can same PHY work with IPV6 network? If yes the why? and if no then what can anyone suggest me a decent chip for it? Thanks
0
votes
1answer
68 views

DC Resistance of Cat5e Cable and Type 2 PoE

I see that the PoE Type 2 standard assumes a maximum loop resistance of 12.5 Ω/100 m, but cat 5e is specified to have maximum loop resistance of 18.8/100 m Ω. Does this mean that PoE type 2 is not ...
0
votes
2answers
164 views

Convert BNC to Ethernet to Coax/HDMI

I need to make a cable run of approximately 150 feet. The source is a security camera box and the destination is a large ~42" television with all the basic hookups. The source box is in a room right ...
3
votes
1answer
191 views

Ethernet Pass Through over PCB

I'm working on a personal PCB design that will include ethernet pass through. Photo attached. Basically just ethernet in from a router, straight over the PCB to ethernet out which will go to a CPU. ...
1
vote
0answers
53 views

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 ...
7
votes
3answers
430 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 ...
2
votes
1answer
76 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 ...
0
votes
2answers
65 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 ...
1
vote
0answers
63 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 ...
1
vote
2answers
70 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 ...
2
votes
2answers
132 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 ...
2
votes
1answer
116 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 ...
0
votes
1answer
56 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 ...
1
vote
1answer
47 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 ...
0
votes
3answers
324 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 ...
1
vote
2answers
131 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 ...
-2
votes
4answers
181 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 (...
5
votes
2answers
203 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 ...
0
votes
1answer
130 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 2-...
0
votes
3answers
86 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 ...
15
votes
7answers
3k views

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 ...
2
votes
1answer
134 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 ...
0
votes
1answer
58 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 ...