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Using 100base-tx serial encoding over ethernet

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Using 100base-tx serial encoding over ethernet

Postby Maziar » Fri Feb 26, 2016 8:15 am

Hi

I need decode 100base-tx ethernet

have any one can do it ?
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Re: Using 100base-tx serial encoding over ethernet

Postby Martyn » Tue Mar 01, 2016 1:32 pm

What length of time are you trying to decode the ethernet data for ?
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Re: Using 100base-tx serial encoding over ethernet

Postby AndrewA » Tue Mar 01, 2016 3:15 pm

Hello Maziar,

The 3406D has enough analog bandwidth to for the decoder work correctly. Even our 6404D and 6407 scopes will be limited by size and number of packets when decoding. These models could used to look at the eye diagrams, but one of our 9000 series units would be the best for eye diagrams.
Currently for the 100base-tx decoding to work correctly, you need to set 'between rulers' or limit the number of samples, to be no more than 20MS. This is a bug in PicoScope 6.11.10.

Are you want to just decode the packets, or look at the signal quantity? - eye diagrams?

If you want to decode the packets, I would use a PC/laptop using the NIC and LAN tap and run TCP/IP decoding software like wire-shark, which is free. https://www.wireshark.org
LAN tap- https://greatscottgadgets.com/throwingstar/ Or make something with the same connections.
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Re: Using 100base-tx serial encoding over ethernet

Postby Maziar » Tue Mar 01, 2016 5:27 pm

i buy this scope when 100Base-TX listed in : https://www.picotech.com/oscilloscope/3 ... c-analyzer



AndrewA wrote:Hello Maziar,

The 3406D has enough analog bandwidth to for the decoder work correctly. Even our 6404D and 6407 scopes will be limited by size and number of packets when decoding. These models could used to look at the eye diagrams, but one of our 9000 series units would be the best for eye diagrams.
Currently for the 100base-tx decoding to work correctly, you need to set 'between rulers' or limit the number of samples, to be no more than 20MS. This is a bug in PicoScope 6.11.10.

Are you want to just decode the packets, or look at the signal quantity? - eye diagrams?

If you want to decode the packets, I would use a PC/laptop using the NIC and LAN tap and run TCP/IP decoding software like wire-shark, which is free. https://www.wireshark.org
LAN tap- https://greatscottgadgets.com/throwingstar/ Or make something with the same connections.
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Re: Using 100base-tx serial encoding over ethernet

Postby Maziar » Wed Mar 02, 2016 5:49 am

i try test with between rulers no any 100base-tx packet show in serial decoding for it :-) :?
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Re: Using 100base-tx serial encoding over ethernet

Postby AndrewA » Fri Mar 04, 2016 2:03 pm

Hi Maziar,

I have attached diagram of a LAN tap cable to make for using with our 10/100 BASE ethernet decoding.
You can either make the cable from scratch or splice a existing patch cable, and add the BNC connectors.
This will only work with scopes with 1M ohm input impedance.
Also shown is a screen shot from a 3207B series scope setup with 100 BASE TX Ethernet decoding setup.
The captured waveform on a 3X06D is good enough for decoding, but not for looking at signal integrity.
You would use one of our 9000 series scope if wanted to check signal integrity. (But you would need to use a different cable)
Ethernet 10_100-BASE Scope LAN Tap.png
Ethernet 10_100-BASE Scope LAN Tap

100BASE-TX uses one signal pair for transmission and another pair for collision detection and receive. The transmission occurs at 125 MHz frequency operating at 80% efficiency. It employs a three-level, MLT-3 line encoding signalling scheme. The lines are never idle like 10BASE-T as 100BASE-TX uses bit stuffing in the transmission. So there is no way tell if you sending packets or not, by looking at the trace.
The peak to peak level is around 2v, with an impedance specified as 100 Ω ± 15%.
Note- 10BASE-T ethernet uses a different encoding method.
Ethernet 100-BASE-TX 3207B.png
Ethernet 100-BASE-TX 3207B

Remember you must limit the number of samples that the serial decoding uses to 20MS.
So either set the number of samples to capture to 20MS or use set the serial decoding to 'between rulers' so if you have 100MS across the screen set the time rulers to no more than 2 divisions.(20MS)
Ethernet 100-BASE-TX 3207B.psdata
Ethernet 100-BASE-TX 3207B
(612.29 KiB) Downloaded 51 times
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