New answers tagged

1

The real professional way is using a TDRM (time domain reflectometer). It locates the impedance mismatch so it flags where the pair is broken. These things are expensive but I once located rodent damage with less than 50cm of error on a floor run. The real question with ethernet cable is… what will you do after finding the fault? Most of the time the correct ...


2

Asynchronous for sure. Commonly for a bus synchronous means there is a separate clock signal used by the receiver to sample the data. Ethernet: no separate clock, and clock signal is recovered from the encoded wave pattern. RS232: no separate clock, and the sampling clock is generated from native clock at the receiver. So you need to tell the receiver the ...


3

Ethernet, in its various forms, embeds clock timing in the stream (such as the Manchester encoding used for original 10Mbit Ethernet), or provides a means to identify and recreate the clock to properly decode symbols using special markers. Either way, the timing for this embedded clock comes from the transmitting source, and the receiver is obliged to ...


2

Ethernet wave forms bring both data bits and synchronization bits. Clock bits are encoded in the waveform and are recovered in realtime by the receiver. The receiver uses the recovered clock bits to synchronize the recovery of the data bits. Ethernet is a synchronous interface because the stream contains both data and clock information.


10

Ethernet has no separate wire for clock signal, so does it make it asynchronous? Not having a separate wire means nothing. Some ethernet data uses Manchester encoding and some use data scrambling. Both allow the receiver to lock-in to the data and are therefore regarded as synchronous. Note that you don't need to transmit clock separately to data to have a ...


17

I think you're getting multiple answers, because the real answer is that you can't quite wedge what the various flavors of Ethernet are into the definitions of "synchronous serial" or "asynchronous serial". In fact, not all Ethernet flavors are entirely serial, because they involve parallel wires. Ethernet has no separate wire for clock ...


5

It really depends on which particular Ethernet interface is in question, there is no "the" Ethernet interface so there can be no single answer. For example, Ethernet between a MCU and PHY typically uses the MII bus, which is synchronous interface. It even has two clocks, one for transmitting data, and one recovered for receiving data. The RMII ...


1

If you suspect the ferrite bead: You can use a spice model for your ferrite bead and simulate it with your actual caps values on both ends, see if that gives a spike in the frequency response. Ferrite beads become resistors at HF, but at low frequency they're inductors, so with low-ESR ceramic caps you can get nasty ringing and spikes at some tens of kHz. If ...


6

The only correct answer is: It depends. For an ethernet signal like the one Ben Eater is inspecting in that video, it fluctuates between +1 V and -1 V. For I²C, it goes between 0 V and the supply voltage for the chip, whatever that may be. For RS-232, it goes between +15 V and -15 V. For USB, it goes between 0 V and 3.3 V (yes, even though the power supply ...


2

Yes. The first step is to inspect or replace the RJ45 jacks installed on each end of the cable being tested.


0

A long asleep thread, but I thought I'd add a few options to it in case someone else is looking. Microchip have a number of quite low port count options https://www.microchip.com/en-us/products/high-speed-networking-and-video/ethernet/ethernet-switches (3port, but only 2x PHY.. so an external PHY might be required) https://www.microchip.com/wwwproducts/en/...


0

Perhaps someone will come along with a better 'answer' later. But the conclusion here is pretty much just "it'll be fine". In the Ethernet PHY world, there are two different methods of driving the differential pairs, current-mode and voltage-mode. If using current-mode, then coupling transformers will always be required. If using voltage-mode, then ...


1

This is a rather vague and broad question, but I’ll attempt an answer. Ethernet IEEE 802.3 was originally and primarily intended for remote communication between devices using coax, twisted pair, fiber, and even radio. Ethernet may be used for local networks such as within a building, or regional metropolitan networks (MAN). Ethernet is also used for very ...


1

Ethernet is a way to connect, mostly, two computers, or a computer or many computers to a printer, or scanner, and so on. Ethernet specifies how its OSI Layer 2 is, and it can be implemented via several different OSI Layer 1: for example, 10BASE-T, 100BASE-T, 1000BASE-T are very similar, but with different speeds. Ethernet is used between computers, printers ...


0

You can have a look at this question which explains the difference between Ethernet and CAN. Ethernet, CAN, RS232, RS485 are Buses used to carry information over cables that can be disconnected. They usually are protected against ESD and uses some sort of transceiver. It is basically buses that goes over longer distance and communicate between different ...


-2

I edited this answer because it contained errors. Ethernet is one of the most important I/O interface. Ethernet was invented in the 70's. Ethernet is nowadays galvanically isolated. Ethernet is meant for high distances: up to 100 m on copper. Ethernet is a high speed differential interface on copper. Ethernet is an IEEE standard interface: 802.3 Ethernet is ...


0

There are some huge differences at the protocol level, other than the physical cabling issues. First of all even CAN has a controlled impedance transmission line at 120 ohm (in fact ethernet twisted pair is one of the best CAN cable available), it's just much more tolerant. CAN is designed as a stubbed bus system while Ethernet is in star topology (at least ...


Top 50 recent answers are included