Laserjet causes collisions on a hub, why?

Archived from groups: comp.sys.hp.hardware (More info?)

On the seventh day, Andrew Bullock wrote...

> Hi
>
> I hope you can help me,
>
> I have a home network consisting of a router/switch (SMC Barricade 4pt),
> a hub (Ether Prime 4pt, 1Uplnk), a jetdirect print server, and a
> laserjet 4 plus printer.
>
> plugging the printer into the router/switch works
> plugging the printer into the PS - into the router works
> plugging the printer into the PS - into the hub - into router works
> plugging the printer into the hub, which plugs into the router/swtich
> doesnt work.
>
> the hub has an Rx light (green) for each port and a PAR light (red).
> when i plug the printer in, the respective PAR light goes red and the
> collision light flashes.
>
> Can someone suggest why this is happening please, and if there is a way
> to fix it?

I have to admit that I don't understand you in all necessary detail but I
suggest you check cable, speed and duplex modes as well as autonegotiation.
Collisions usually occur on
-switches when devices are set to half duplex
-hubs by design.

If one device is set to use a fixed duplex mode (normally full-duplex) and
the switch uses autonegotiation, network speed will dramatically decrease.
On hubs, the use of full duplex will lead to error (hubs can only use half
duplex). Some cheap devices use autonegotiation and cable detect but are
unable to tell the correct speed when uplinking to another hub/switch.

I hope this gets you underway to solve your little mystery ;-)

HTH

--
mit freundlichen Grüßen/with kind regards
Christian Dürrhauer, Institute of Geography, FU Berlin

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Someone Else Who Will