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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Impedance matching components with Ethernet

I’m designing a small switching circuit for 1000Base-T Ethernet and have a concern regarding impedance. The board design consists of 3 shielded Ethernet jacks and 4 DPDT relays (here) made for high ...
3
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2answers
176 views

Why is Bob Smith termination for Ethernet recommended if it's wrong?

I came across this article today (more detailed paper), which claims that the widely recommended Bob Smith termination (75-ohm resistor + 1000pF to chassis GND) may not be ideal (or correct). If this ...
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2answers
47 views

Ethernet Port Listener Throughput Maximisation

We have a distributed sensor network (12 nodes), using Ethernet as the backend protocol. These are networked at 100Mb/s to a single 1Gb/s link using a 16-port switch. I've previously seen Java and C ...
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0answers
26 views

Can I generate a 90° Clock signal with Xilinx's ODELAY for RGMII?

Some time ago I implemented a GMII interface for my Gigabit Ethernet core. Now I'm trying to do the same with the RGMII protocol. The reference implementation from Xilinx uses IDELAY[|E1|E2] ...
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2answers
137 views

Why are ethernet ports always upside-down?

I have noticed that in almost every board, RJ-45 Ethernet sockets are always soldered upside-down. Why are these sockets made this way? Wouldn't it be easier to make and solder them with the pins ...
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9 views

Ethernet shield not getting IP [migrated]

I am just running the below DHCPAddressPrinter sketch in Arduino example to setup EthernetShield with MAC and IP ...
0
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1answer
26 views

Does SGMII contain MDIO?

When connecting a NIC (Intel I210-IS) to an gigabit ethernet switch with integrated PHYs (Marvell 88E6176) using the SGMII interface, I came across the following question: Since SGMII is a serialized ...
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1answer
72 views

Purpose of the magnetics center tap in Ethernet [duplicate]

What how the magnetics center tap work in Ethernet HW configuration? I've read that it depends on the specification of the attached PHY, sometimes must be connected to the PHY's DC supply, but i can't ...
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1answer
39 views

Switching between two Ethernet magnetics and one simple Phy

I'm deep into a project and I would like to ask how can I switch 2 ethernet interfaces to single PHY. I know that there're some suitable analog switches for this purpose like MAX4890, but I don't ...
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2answers
54 views

Extend an rj45 Jack

I want to extend the Ethernet port (of my raspberry pi) using a short bit of cable plugges in into the Ethernet Port and solider to another rj45-jack. In the jack I have here, are some built-in coils ...
0
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1answer
72 views

High speed data from microcontrollers to pc using daisy chain

I have STM32F4 discovery boards. I have 30 such boards supporting maximum data of 128Mbps. The max data at any instance in complete system would be 300Mbps.I need to pick this data and send it to PC. ...
14
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4answers
2k views

Are solder bridges on chips always bad?

I just bought my Arduino Ethernet shield – a knock-off one for $10 instead of $60. I connected it up, but it doesn’t work – LEDs light up but do not blink, and no ethernet link is established ...
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4answers
118 views

2000-feet Ethernet connection for Internet and other data

I am building a house. It's located about 2000 feet away from the nearest Internet cable. I had to run our electrical service underground the whole way, and have already installed a conduit for ...
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0answers
33 views

communicating between computer and the board which has a microcontroller

I have a PC and Ethernet module(ENC28J60). I want to connect each other using socket and send data from PC to the Ethernet module. physically both r connected through LAN. I want to make my PC as the ...
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1answer
53 views

How to program enc28j60??

I read enc28j60 is unprogrammable directly from the computer but it has registers that I can program so how can I excactly do this.. is it programmed from the mcu connected to it through spi or is ...
3
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1answer
53 views

Ethernet components location

The normal ethernet components configuration: MAC <-> PHY <-> Magnetics <-> RJ45. My RJ45 connector must be mounted on the system box's front panel, so there must be a wire routed from the ...
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1answer
54 views

Pressure Sensor Calibration

Here's the situation: I need to verify the pressure sensor accuracy of a control board. I have a software to verify the pressure and I am using Ethernet Communication to communicate between my control ...
4
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1answer
300 views

Caculating baud rate of Ethernet per wire

I'm trying to find the answer to what should be a simple question. How do I calculate the physical rate bits are transmitted on an individual Ethernet wire? I am interested specifically in 100 Mbps ...
2
votes
1answer
176 views

Can an RMII phy be connected directly to another RMII phy

I have some Microchip (SMSC) LAN9303 Ethernet switches in my system. The LAN9303 is a 3-port switch which has 2 connections for twisted pair cables and one MII connection. The switch chips are some ...
0
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1answer
187 views

choosing diodes for a passive ethernet hub

I found several guidelines for building a passive ethernet hub, mostly quoting this. The guide specifies which diodes to use, but I cannot find them anywhere. What are the parameters I should search ...
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3answers
94 views

Is it possible to check an Ethernet twisted pair with a multimeter?

It would be useful to measure electrical parameters (such as I,U,R and perhaps L,C or other) at the end of the cable, when the other end is disconnected or connected, and analyze the physical layer of ...
0
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2answers
27 views

How is the capacity of link more for single network link

In networks capacity_of_link = bandwidth*propagation_delay My doubt is how can a same wire carry multiple signals? Is is because the wire is very long (still the wire can be either high or low). I ...
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0answers
63 views

Can a CAN bus support power over ethernet?

I'd like to reduce my loom for a battery box. Every time I run a line i.e. CAN or low voltage power, it has to be isolated from the master controller which communicates with each slave. I'd like to ...
0
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0answers
29 views

Arduino with Ethernet Shield Problem With External Power Supply [duplicate]

I asked this question at Arduino forum but nobody answered. In fact, my question seems familiar but there is a little trick. I use Arduino Mega with Ethernet shields (And also with screw shield) and ...
3
votes
2answers
116 views

Why do serpentine traces (supposedly) entail decreased ESD immunity?

In an Intel guideline for their 82579 Gigabit Ethernet controller I've read (p. 18) that a side effect of using serpentine traces on the MDI (which carries the actual Ethernet signals) leads to ...
2
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2answers
264 views

how to implement Ethernet with PIC, PIC18F97J60, PIC32MX(795F512L), ENC624J600, LAN8720A

My project is a data logger board which must mount a PIC of some kind to provide USB and Ethernet as a means to communicating with the board. I can develop this system into two products a low-end ...
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0answers
96 views

PHY device not responding to MDIO

Update: I have read more about this and what I can conclude is that the phy IC is not initialized correctly. Still no able to figure out how to initialize phy device. Please go through the code and ...
6
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2answers
355 views

Length Matching Differential Pairs

I am routing a PCB with an Ethernet connection and I am having a bit of trouble deciding on how best to route the TX and RX differential pairs. I have done the impedance calculations to figure out the ...
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votes
2answers
70 views

Interface USB to micro controller [closed]

Following thing I want project. micro controller USB interface Ethernet Do I require external USB driver to get USB interface with microcontroller? Is it inbuilt in microcontroller? I am new to ...
0
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0answers
40 views

Can I link Ethernet chips on PCB? [duplicate]

I read up on the Raspberry Pi Compute unit and wanted to link a hand full for networking. Unfortunately, they do not come with native Ethernet, but USB. So I was thinking of linking each compute ...
0
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2answers
55 views

Using ethernet with a camera

I own one of those little pinhole 'spy cameras' that connect to your tv.and are powered by 5v? With an arduino and ethernet shield, would there be a way for me to create an IP camera type thing?
3
votes
2answers
105 views

On-Board connection of ethernet transceivers

Is it possible to connect two 1000-BaseT transceivers with each other? I have two transceivers, each of them has 4 twisted pairs that actually are meant to be connected to an RJ45 connector including ...
1
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2answers
185 views

What is the exact difference between SGMII and 1000Base-X?

I was wondering what the exact difference between SGMII and 1000Base-X is, because both seem very similar. Is the "big" difference only the physical medium they are supposed to be transmitted on? Both ...
0
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1answer
92 views

Termination resistors in Ethernet in Kilo-Ohms instead of Ohms?

When working with Ethernet, whether copper or optical fiber, why are the termination resistors always in a few ohms and never in kilo-ohms? Example: 49.9R on transmit & receive pair of PHY in ...
0
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1answer
97 views

Arduino - receive Ethernet W5100 signal to multiple arduinos

I'm after doing a device in which I'll use 4 AtMega328 chips; Since they'll all be mounted on the same PCB, and I need an ethernet connection for them, I was wondering if there's a way to share the ...
0
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0answers
274 views

LAN9512 USB hub and Ethernet Controller Problems

I'm working on a custom board using a Raspberry Pi computer on module (COM) (info and schematics here: http://www.raspberrypi.org/raspberry-pi-compute-module-new-product/. The board is based on the ...
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2answers
98 views

What purpose do transformers have in electrical interfaces such as ethernet? [duplicate]

Some electrical interfaces, such as ethernet, specify that the outward-facing socket are to be isolated by a transformer. For instance, see this circuit example from the data sheet of an ethernet ...
0
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1answer
72 views

CAT5/6 to non RJ45 connector assemblies

What types of non-RJ45 cable assemblies plugs/sockets are common? I need to carry instrumentation signals (8 of them) which are a mix of small signal and 60Vpp. I cannot use RJ45 in case someone ...
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0answers
96 views

Implementing and debugging LwIP

How should I start working with LwIP stack? I've STM32F429 processor with LAN8720AI on board and my task is to program simple project which will show ethernet working properly. I tried to configure ...
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1answer
63 views

FIFO in ethernet module

In Ethernet module , why do we need FIFO block before the mac layer ? Can we bypass it ? Thanx in advance
4
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3answers
241 views

Why does Ethernet on UTP have much greater range than other modern protocols?

OCuLink, SATA, USB 3, and Displayport all provide on the order of a few Gbps per signaling pair, and are limited to a cable length of just a couple meters. Ethernet via comparable cabling provides ...
0
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1answer
71 views

Do I need to cross my Tx and Rx for an Ethernet AUI interface device?

I have one device with an AUI Ethernet interface coming out of a non-standard connector. I'm making a cable to attach the device to a COTS transceiver which contains the standard D-Type AUI connector. ...
1
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1answer
71 views

which devices on network use CSMA/CD

CSMA/CD 's definition based on wikipedia is : Carrier Sense Multiple Access With Collision Detection (CSMA/CD) is a media access control method used most notably in local area networking using ...
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0answers
58 views

Ethernet pass through connector on bottom of IP phone. What do you reckon is inside?

I was hooking up some 10/100BaseT Ethernet cables at a customer site and I noticed that the Voice Over IP phone on a desk had an Ethernet input and an additional RJ45 that serves as a pass-through ...
5
votes
1answer
432 views

Bob Smith Termination with POE

I'm looking into doing a Bob Smith termination for a Power over Ethernet (POE) PSE. The TI app note shows the following termination: But all of TI's reference designs (and later figures in the same ...
3
votes
2answers
95 views

Why does a Category 5 rated jack have different solder tail positions than a traditional jack?

I am attempting to specify a replacement part for a modular jack used in an original design (I basically need something that will stick out farther than the original). However, the part I would like ...
0
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0answers
316 views

Ethernet: are Tx and Rx reversed in this schematic? What are the consequences?

On the Ethernet section of the schematic given for the BeagleBone Black (rev C) we see pins TXP and TXN of the LAN8710A PHY going to pins 3 and 6 of the component labeled LPJ0011BBNL (manufacturer: ...
0
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3answers
263 views

How does “bidirectional” transmission on gigabit ethernet work?

I was reading about the various twisted pair protocols, being distracted by the marvels of Wikipedia when I went to look up the way to wire a connector. And I'm wondering how it can transmit in both ...
2
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2answers
207 views

Does the voltage increase on 10Base2 and 10Base5 ethernet when the signal is reflected? Will this trigger the collision detection?

From what I understand, the collision detection will become true when the voltage on 10base2 or 10base5 coax is abnormal. Quote from Wikipedia: If termination is missing, or if there is a break in ...
0
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1answer
100 views

Ethernet UDP diode

I want to create a device of some sort where I am absolutely positive that only UDP traffic can pass one way. Of course I could setup whatever old router I might have, the thing is I want to make it ...