Can I use a Rigol DS1054Z scope to see 10 Mb Ethernet bits?

[TMM]

A 10Mbps NRZ data signal needs >>10MHz bandwidth to be nice and square (defined transitions from one symbol to the next) because to construct a perfectly square edge requires an infinite number of harmonics like a square wave does. 10Mbps will look reasonably square on a 100MHz scope.

100Mbps will look very ugly on a 100MHz BW scope with symbols looking more like a sine wave than a square wave.

[CharlieEcho]

The 10 in 10baseT actually refers to MHz not megs so yeah, you're good.

Umm, no, it expressly refers to 10Mbps, not MHz. The names of Ethernet variants follow a defined nomenclature described here: https://en.wikipedia.org/wiki/Ethernet_physical_layer#Naming_conventions

Hrrm. That's how I first learned it, then I was corrected by an instructor I trusted who insisted it really designated frequency, of which transfer rate was a function. Before smartphones, so I just accepted it as it didn't matter much to me at that time. Wiki certainly agrees with you. Some vendor websites seem to go the other way. Or....both? A random example:


[from http://www.sopto.com/learningcenter_learningcenter_34/differences_of_10base-t,_100base-t_and_1000base-t.shtml ]
Definition - what does “10, 100, and 1000”, “BASE” and “T” mean?

The "10" "100" "1000" in the media type designation refers to the transmission speed of 10,100, 1000 Mbps, they represents the frequency in MHz (Mega HertZ) for which this cable is made. They represent for 10MHz, 100 MHz, and 1000 MHz. The greater the MHz, the greater speeds the cable can handle.

The "BASE" refers to baseband signaling, which means that only Ethernet signals are carried on the medium. (Through repeaters, media segments of different physical types can be sometimes be used in the same system.) The "T" refers to "Twisted Pair" physical medium that carries the signal. This shows the structure of the cable and tells us it contains pairs which are twisted.

 The IEEE wins, naturally, but

[CharlieEcho]

A 10Mbps NRZ data signal needs >>10MHz bandwidth to be nice and square

Not to derail a derail, but does this imply a NRZ hard drive analyzer scope probe (meant for IDE) can be used on Ethernet?

[JohnBee]

>Quote from: alsetalokin4017 on Today at 03:19:12 AM

... and keep your fingers crossed that your cheap Chinese probe doesn't have some internal problem like poor insulation ...   

Actually it _could_ be simpler: Just don't do it.   

We could say the same for any piece of equipment however.
With that said, I just don't see the need for such drama when all that's needed, is to eliminate(as it remove) the ground lead from the probe.

PS. I wouldn't recommend that anyone work with household current without a proper understanding of what it is they're working with. Though I don't think it's necessary to renounce that doing so would need to be as dangerous as people are making it out to be - my two cents of course

[DougSpindler]

I don't see what all the fuss is about tbh. if you're going to probe the main, then just don't use the ground lead - couldn't be simpler really

Exactly  Or use an isolation transformer.

[DougSpindler]

I don't see what all the fuss is about tbh. if you're going to probe the main, then just don't use the ground lead - couldn't be simpler really

... and keep your fingers crossed that your cheap Chinese probe doesn't have some internal problem like poor insulation ...   

Actually it _could_ be simpler: Just don't do it.   

Guess you have not worked with American equipment.  Can't tell you the number of times I have purchased and installed name brand American Made devices and upon first plug-in they explode?  And these were safety devices to protect our equipment.  For some items I will pick Chinese over American every time. 

[DougSpindler]

A 10Mbps NRZ data signal needs >>10MHz bandwidth to be nice and square

Not to derail a derail, but does this imply a NRZ hard drive analyzer scope probe (meant for IDE) can be used on Ethernet?

Great derail question.....  I would think so.  A scope is a scope.  The problem is you probably do not have frame decoder for Ethernet.

Woul you mind messagining me?  I have some very tecnical hard drive questions I've been trying to get answered for years.  The answers I've been given just don't pass the critical thinking challenge test.  Or do you wnat me to create a new post?  If so, which forum?

[CharlieEcho]

I'm probably not the person for that! I've never tried to get into low-level HDD debugging, I just see the disused probes floating around eBay.

[ez24]

DO NOT PLUG THE SCOPE PROBES INTO THE WALL. That will be the end of it (or at least the channel).

Also you might have breathing and hearing problems because in my case the ground lead exploded and I had to get out of the room.  I checked the fuse in the AC line and it was a 30a screw in.  Now I would only do it if I had a gun to my head.

It one of those things you can talk about (if you live).  A very very stupid thing to do.  I now assume it is a good 60Hz signal.

[TomS_]

I'm a college instruction teaching sever virtualization, Windows Server and computer networking (hubs routers switches).  So I'm more of a hobbyist than an EE.    I just managed to buy a Rigol DS1054Z scope.  I'd like to know if I can see an Ethernet bits/wave form on the screen.

Looking at Ethernet this way isn't useful for an average IT professional or network engineer. It doesn't add any value.

You are better off with Wireshark and looking at how the various protocols stack up within an Ethernet frame in order to make all of this work.

Teaching people how to use Wireshark for troubleshooting would be wayyyyyy more worthwhile to the industry as a whole than seeing bits on the wire...!

[tooki]

The 10 in 10baseT actually refers to MHz not megs so yeah, you're good.

Umm, no, it expressly refers to 10Mbps, not MHz. The names of Ethernet variants follow a defined nomenclature described here: https://en.wikipedia.org/wiki/Ethernet_physical_layer#Naming_conventions

Hrrm. That's how I first learned it, then I was corrected by an instructor I trusted who insisted it really designated frequency, of which transfer rate was a function. Before smartphones, so I just accepted it as it didn't matter much to me at that time. Wiki certainly agrees with you. Some vendor websites seem to go the other way. Or....both? A random example:


[from http://www.sopto.com/learningcenter_learningcenter_34/differences_of_10base-t,_100base-t_and_1000base-t.shtml ]
Definition - what does “10, 100, and 1000”, “BASE” and “T” mean?

The "10" "100" "1000" in the media type designation refers to the transmission speed of 10,100, 1000 Mbps, they represents the frequency in MHz (Mega HertZ) for which this cable is made. They represent for 10MHz, 100 MHz, and 1000 MHz. The greater the MHz, the greater speeds the cable can handle.

The "BASE" refers to baseband signaling, which means that only Ethernet signals are carried on the medium. (Through repeaters, media segments of different physical types can be sometimes be used in the same system.) The "T" refers to "Twisted Pair" physical medium that carries the signal. This shows the structure of the cable and tells us it contains pairs which are twisted.

That’s definitely and provably wrong, because the higher Ethernet speeds have bitrates far higher than the cables’ spectral bandwidth. Gigabit, for example, uses all 4 pairs, as four bonded 250Mbps bidirectional links, running on Cat 5/5e cable, which has bandwidth of 100MHz. Look at the last table on https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair#Variants — it shows the spectral bandwidths of the signals, as well as of the cables they’re supposed to run on. 10BaseT is the only one where the data rate and the spectral bandwidth are the same!!

Whoever wrote that random example was literally just making it up — just look at what they think “baseband” means! 

[CharlieEcho]

Hah, yeah, OK. That's pretty conclusive.

[Mr. Scram]

I don't see what all the fuss is about tbh. if you're going to probe the main, then just don't use the ground lead - couldn't be simpler really

I suppose you could even use the ground lead, as long as you are very sure what is the live wire and what's neutral, right? Neutral to neutral/ground shouldn't do much.

Of course, there are a few unexpected things that can ruin your day, so whether it's advisable is another thing. It's easy to make a mistake and thoroughly ruin the equipment, possibly hurting people in the process.

[CharlieEcho]

So, my apartment's central panel lacks a main breaker. And I want to add a network connected power monitor.

In theory, I know enough to install the thing safely. One hand in my back pocket, install the clamps on the phase feeds, no sweat.

In practice, either the power company is going to agree to help me out by disconnecting the service at the meter for a few hours, or I'm going to hire an electrician to do it. (And install a main breaker too, wtf...)

[DougSpindler]

So, my apartment's central panel lacks a main breaker. And I want to add a network connected power monitor.

In theory, I know enough to install the thing safely. One hand in my back pocket, install the clamps on the phase feeds, no sweat.

In practice, either the power company is going to agree to help me out by disconnecting the service at the meter for a few hours, or I'm going to hire an electrician to do it. (And install a main breaker too, wtf...)

How did that happen?
Just pull the power meter.  The connector and similar to spade connector.  Just rock the meter back and forth and it will come off.  Lot of YouTube vids on how to do it.  Quite safe and easy to do.  Just remember the two lugs on the top are connected directly to the power company.  Once you are done, press the meter in place. 

Buy a pair of welders gloves for protection.  About $5.00 at Harbor freight.   

[DougSpindler]

DO NOT PLUG THE SCOPE PROBES INTO THE WALL. That will be the end of it (or at least the channel).

Also you might have breathing and hearing problems because in my case the ground lead exploded and I had to get out of the room.  I checked the fuse in the AC line and it was a 30a screw in.  Now I would only do it if I had a gun to my head.

It one of those things you can talk about (if you live).  A very very stupid thing to do.  I now assume it is a good 60Hz signal.

So do you understand and would you share what went wrong?

[DougSpindler]

I'm a college instruction teaching sever virtualization, Windows Server and computer networking (hubs routers switches).  So I'm more of a hobbyist than an EE.    I just managed to buy a Rigol DS1054Z scope.  I'd like to know if I can see an Ethernet bits/wave form on the screen.

Looking at Ethernet this way isn't useful for an average IT professional or network engineer. It doesn't add any value.

You are better off with Wireshark and looking at how the various protocols stack up within an Ethernet frame in order to make all of this work.

Teaching people how to use Wireshark for troubleshooting would be wayyyyyy more worthwhile to the industry as a whole than seeing bits on the wire...!

I teach both, but you are right Wireshark is far more useful.  The scope allows students to "see" what's happening on the wire.  Or look at it this way.  There are analog and there are digital scopes, right?  Seeing Ethernet traffic on an scope is like using an analog scope.  You are seeing exactly what's on the wire.  Wireshark is like a digital scope.  It's decoding the packets, and there can be instances where what Wireshark has decoded is not accurate.