SUN networking problems

From: Arno Kletzander <>
Date: Sun Mar 25 23:28:34 2001

Hi folks, we powered up the working pizza box and the laser this weekend. At
first we got a lot of
le0: no carrier - transceiver cable problem?
style errors during bootup and in the console window, but they disappeared
when we re-seated the AUI cable on the SUN. Unfortunately, that was not all of
the problem. If you now try to print to pa3 (which is the CalComp?s name),
the job is stored in the printer queue, but there also appear a number of
error messages "No answer from host pa3 on parallel port" when you LPQ for it.
PINGing for the printer ends up with "no answer from pa3".
Is the SUN trying to send the data to a parallel-port printer although the
CalComp is on the Ethernet?

Peter Turnbull wrote:
>Do those transceivers have a set of LEDs on them? I suspect not, but that
>might tell you if anything is being transmitted/received.

On the transceiver connected to the SUN, the PWR (green) and SQE (yellow)
LED are alight as long as the system is powered up. The only (green) LED on the
printer?s transceiver is also on as long as the printer is.
If I connect the printer to one of the 3-LED transceivers, the PWR LED is on
all the time and the other two give very short flashes when the printer has
completed its warming-up cycle and is in ready mode.
There are also three LEDs on the back side of the printer next to the AUI
connector; two of them (green and orange) illuminate during the warming-up
phase, then the orange one goes out and the green one begins to flash.
I have not noticed any flickering etc. of LEDs when trying to print or ping.

Tony Duell wrote:
>How hard is it to swap over the transceiver cables between the 2 Suns? If
>it then works, you know the problem is either the transceiver that used to
>be connected to the working sum, or a nasty problem caused by reflections >on
the cable

It is very easy, as the machines stand nearly side-by-side on two
neighboring desks and the cable (with the four Transceivers on it) is coiled to a ring
and lying behind them. (No, not a very tight ring or one with sharp
bends?n?twists in it
) I haven?t yet had the time to try it, but:
If I connect the printer to one of the 3-LED transceivers, the PWR LED is on
all the time and the other two give very short flashes. However,
transmission of data isn?t possible either.

Bill Gunshannon wrote:
>First, "a piece" of yellow cable won't work. The lengths were part of the
>spec and very important. Having to do with reflections and such (anybody
>here still have a TDR??)

I already mentioned the network ran on our ?piece? until we installed that
new tap and transceiver, and that didn?t change it?s length as it wasn?t
inserted after cutting the cable apart but only connects by its contacts
penetrating the insulating layers of the cable. I know that the length is an integer
multiple of 2.5m (2.5m between the black bands and 1.25m between outmost band
and terminating resistor on each end) and my guess goes towards a total
length of either 12.5m or 15m (5 or 6 times 2.5m).

Tony Duell wrote:
>The black bands should be every 2.5m (+/- 5cm) along the cable.
>There must be only a minimal 'stub' between the cable and the transceiver
>(<3cm seems to be the accepted value)
Bill Gunshannon wrote:
>Second, The cable is marked with black stripes. The taps must go on these

As the cable already came from the factory with the bands on it (I was told
that), they should have the correct spacing (I really didn?t want to uncoil
all that stuff just for measuring!) and on the transceivers that already were
on the cable, the band is:
-in one case, inside the tap block
-in two cases 1 and 2cm out of it (which means ca. 6cm away from the core
contactor pin).
We placed the new one also in such a way that the band is now inside the tap
and not visible from the outside.
How about the distance terminator to first tap? I measured here about 1.25
meters, which would be half the tap-to-tap distance. As I don?t know much
about signal transmission in Coaxes, does this make as much sense as it seems to?

Thanks for all given and coming help on solving this.

Arno Kletzander

GMX - Die Kommunikationsplattform im Internet.
Received on Sun Mar 25 2001 - 23:28:34 BST

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