[Solved] Changing NIC speed to 10baseTx

minskpower · Last edited by minskpower on Sat Feb 24, 2007 6:58 pm; edited 1 time in total

I need to change the speed of my RTL8139 NIC to 10base. I've tried ethtool and ifconfig without success.
Apparently everybody wants to change it upwards, not downwards.
Can anyone point me to the right direction? Thanks.

PS RTL driver 8139 is built inside the kernel, not as a module.

erik258 · Posted: Sat Feb 24, 2007 5:59 pm Post subject: ethtool

are you sure you need to? Link autonegotiation usually works.

minskpower · Posted: Sat Feb 24, 2007 6:57 pm Post subject:

Erik! Thank you

You missed my point, I needed to force it to 10Mb, the device is capable of auto neg but the other end has 100. When I ran ethtool with -s eth3 speed 10 it didn't do anything. The man page didn't help much either.
But now your hint about autonegotiation gave me the idea to turn that off first, and THEN to force it to 10base. So it worked.
I've read countless posts via google stating the same problem. I hope this page will get indexed

So to summarize: first turn off autonegotiation, then apply desired setting:

erik258 · Posted: Sat Feb 24, 2007 7:46 pm Post subject:

i considered mentioning the turning autonegotiation off first thing, and mused to myself about whether it would be taken from that I mentioned it. I'm therefore glad you figured it out.

if you don't mind my asking, why do you need to force 10mb/sec?
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minskpower · Posted: Sun Feb 25, 2007 8:36 am Post subject:

Because of terrible RFI comming out of my ethernet cables. One of my neighbours is radio amateur and complained several times about the interference.
As it turns out, switching to 10mb solves this issue.

erik258 · Posted: Sun Feb 25, 2007 6:47 pm Post subject:

How very interesting! I had no idea that shielded CAT-5 would produce radio interference. I guess they are just twisted-pair, which doesn't necessarily count as 'shielding,' but still, I am surprised to learn this. I wonder if your neighbor used frequencies that corresponded too well with the frequency of the ethernet transmissions?
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minskpower · Posted: Sun Feb 25, 2007 8:13 pm Post subject:

My cables are unshielded CAT-5 and apparently they should not generate interference by themselves, with phase cancellation and everything.
However digging the web for info I found an interesting page: http://www.ldblake.ca/radio/netproblem.htm

I don't have such a router, but I suspect my crappy 5-port switch was acting the same way and the 2nd, 3rd and 4th armonics were stepping all over his working bands.
In fact I'm sure this was the problem because once I switched to 10base he said his radios went dead quiet.
When I get a brand name switch I guess I'll be going back to 100mb

erik258 · Posted: Tue Feb 27, 2007 12:11 am Post subject:

I'm looking forward to hearing whether that works. I have never heard of anything like this! In fact my roommate and I run computers unshielded in an old stereo cabinet converted to a motherboard rack, and we haven't had any problems yet. I have dozens (well, probably 15-18) net cables running around and never have a problem... but then again, I never listen to, let alone communicate over, radio.

If you think of it please mention whether that makes the problem dissapear.
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