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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2answers
46 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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0answers
38 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
votes
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 ...
2
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4answers
109 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 ...
0
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0answers
28 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
43 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
votes
1answer
44 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
52 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
284 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
139 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
174 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 ...
0
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3answers
81 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 ...
0
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0answers
52 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
28 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
114 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
votes
2answers
225 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 ...
1
vote
0answers
90 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
votes
2answers
278 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 ...
-5
votes
2answers
66 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
votes
2answers
54 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
99 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
vote
2answers
116 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
68 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
87 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
215 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 ...
1
vote
2answers
88 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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0answers
56 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 ...
1
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0answers
83 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 ...
1
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1answer
59 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
2
votes
2answers
193 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
votes
1answer
62 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
62 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 ...
0
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0answers
56 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
347 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
92 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
266 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
203 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
votes
2answers
196 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
votes
1answer
94 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 ...
0
votes
0answers
55 views

Are there link pulses when autonegotiation on ethernet is off (force speed and duplex)?

I read this. Is it correct that there is no link pulse when speed and duplex are forced (autonegotiation turned off)?
1
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0answers
35 views

On bus Ethernet, how a connected station detect link connectivity?

On point to point Ethernet, link pulse is used between 2 connected devices to detect link connectivity. Reference On bus Ethernet, how a station connected to Ethernet bus detect link connectivity?
8
votes
1answer
410 views

Effects of impedance matching between 50 and 75 Ohm coaxial cables for 10 Mbit/s, Manchester-coded signals (20 MHz)

TL,DR: This is quite a bunch of text because I have included plenty of background info. However, there will finally be a good, and precise question: Should I use an impedance matching network when ...
0
votes
1answer
173 views

Current over CAT6 ethernet cable

How much current can a CAT6 cable reliably handle? I want to use 3 of the cores for +5V and 3 cores for GND. I'm wondering at what current I need to think of another power solution.
0
votes
0answers
162 views

Arduino won't connect to Internet

I recently bought an Arduino Ethernet shield which I want to use with my Arduino Duemilanove ATmega 328. I connected my ethernet shield with my Arduino board and connect shield with my router using ...
1
vote
1answer
100 views

Ethernet: Why is the link status “down” when there is a speed mismatch?

For any networking (ethernet) equipment, the link status (layer 1) is down when there is a speed mismatch between two ethernet interfaces (say: one is 10 Mbit and another is 100 Mbit). Is it ...
0
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0answers
73 views

Carrier Wave in Wired Data Networks

I know this must be trivial for many... Which are the main reasons why line data is not modulated/demodulated in normal enterprise wired networks (in the sense that discrete voltage levels are used)? ...
11
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1answer
1k views

Why is Ethernet not intrinsically safe?

I understand from a training session that ProfiBUS is considered intrinsically safe, while ProfiNET is not. Some googling indicates that ProfiNET can never be intrinsically safe, because Ethernet can ...
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3answers
704 views

Maximum cable length for 5V or 3.3V I2C, UART, or 1-wire signals over Ethernet and how to increase it?

I know similar questions have been asked before (Maximum cable length for 3.3V UART signals) but I would like to know the answer more specifically for a hobbyist. I've been experimenting connecting ...