[Ti] TiBook and powered ethernet

[Jeffrey K. Lew]

>I've noticed a problem when plugging into a powered ethernet jack 
>(which should more properly be called a powered Cat5 twisted pair 
>jack.)
>
>We have IP phones in our office which are powered from the ethernet 
>switch. There is a second auxiliary Cat5 jack in the phone in which 
>you can plug your computer. It is not powered.
>
>If I plug the TiBook into the phone, I get a DHCP address just fine 
>and it works great. If I plug the TiBook directly into the powered 
>wall jack, the TiBook either gets no address or self-generates its 
>own class B 169.254 address and I cannot send/receive on the 
>network. I've tried this in several jacks with the same results.
>
>I've also had a lot of trouble with drop cables, finding that many 
>do not work in my TiBook but do fine in others. I am suspecting I 
>might have a problem with alignment or pin deformation in my 
>ethernet jack, and need to look into this with a magnifying glass, 
>but it may or may not be related to the powered jack problem.
>
>Anyone else notice problems or difficulties making a good connection 
>via a powered ethernet jack or have any ideas to help diagnose what 
>might be the cause?
>
>I have the only PowerBook in an all Wintel shop, so I really, really 
>want to avoid having any kind of connection trouble in front of 
>others :-)
>--

I have a problem connecting to this one switch underneath a 
workstation table--just endlessly attempts to auto-sync up 100baseT 
and keeps failing, and also fails to at 10baseT. Other computers (PC) 
have no problem. I have no problem connecting anywhere else on our 
network, or my own 100/10BT hubs. Connecting to the same brand switch 
elsewhere also gets the same behavior, so there's some compatibility 
problem between Apple's ethernet NIC in my Ti400 and this (and 
possibly other) specific brand of ethernet switch.

However, if I change the configuration from "autoselect" to a forced 
10baseT connection, I can sync to that switch. In Terminal, I just 
use "sudo ifconfig en0 media 10baseT/UTP mediaopt full-duplex" and 
I'm in business, until I have to unplug and plug back in.

Jeff Lew
UCLA Atmospheric Sciences