Hi Jim,

As a basic test you can make an RJ45 connector that connects the EUT TX lines 
to the RX lines thus looping back the Ethernet interface onto itself. This 
certainly works for 100BaseTX because the EUT sees it's own Link Test Pulse, 
assumes it is connected to another Ethernet interface and then activates it's 
scrambled_idle packet mode. This is a 100BaseTX PRBS sequence that maintains a 
net 0Vdc bias on the lines which is used to get round the issues with first 
pulse as seen on 10Base-T

Advatanges of this method
- it doesn't require other equipment in the chamber / test area
- very cheap to make
- no software support required so useful for a at the start of EUT validation 
testing

Disadvantages
- the EUTs PHY (and maybe a bit of the MAC) is the only part of the EUT 
Ethernet interface that is activated. As other posters have pointed out, 
pinging, file transfer will generate electrical activity futher up the 7-layer 
OSI model
- you might not be able to ping or generate traffic at all as the EUT might 
figure out it is connected to itself and redirect traffic internally (this 
statement is a guess)

I would imagine that it would work with Gigabit as this should use 
scrambled_idle packets as well.

If you want to use an application to get data moving over a network connection 
I would highly recommend using iperf (http://sourceforge.net/projects/iperf/) 
which is primarily a network testing tool. It transfers far more data than 
ping, can do bidirectional data transfer and if highly configurable. The 
command line interface is easy to use, can't comment on the jperf GUI. 
Disadvantage against ping is that it requires iperf to be running on both ends 
of the link whereas ping doesn't

Hope this helps
James



________________________________
From: Knighten, Jim L [mailto:[email protected]]
Sent: 28 December 2011 00:05
To: [email protected]
Subject: [PSES] What means do you use to exercise Ethernet telecom ports?

I am curious what means people are using to exercise Ethernet telecom ports 
when testing for conducted emissions according to CISPR 22 and conducted 
immunity according to CISPR 24?

Do you use an external piece of equipment (AE) to send Ethernet traffic?  If 
so, what do you use and do you like it?

My particular interest is 1000BaseT (gigabit Ethernet), but the question is 
more general.

Thanks in advance,

Jim

__________________________

James L. Knighten, Ph.D.
EMC Engineer
Teradata Corporation
17095 Via Del Campo
San Diego, CA 92127

858-485-2537 - phone
858-485-3788 - fax (unattended)






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