[plug] Any used a ThinLan hub before ?

[Denis Brown]

James (and others who may be interested),

If your network is small, for example only a few machines and the physical
end-to-end distance is less than 185 metres on a single segment, then you
don't need a hub (repeater) for working with co-ax (10base2) cable.  You DO
need terminators, however.  I've seen people string together a 10base2
network with audio cable rather than proper 50-ohm co-ax but the results
can be quite flaky!

>wouldn't need any T-pieces or terminators to work since he
>
Segments of thin ethernet (10base2) always require termination at both ends
in order to eliminate standing waves or "ringing" set up by the fast
risetime waveforms of the signals.  It may be that the hub in question will
provide the termination at the hub end, but there will always be a need to
terminate the remote end of the cable.  If the standing waves are allowed
to develop, they will almost certainly cause loss of data, sometimes to the
point where devices connected on the segment will not communicate with each
other.

>it a go.  So far under  Win9x the two PCs which I used cannot see each 
>other.  Haven't tried it under Linux yet. So, I'm not quite sure whether it 
>
Several possibilities include:
a) one or both of the PC's network cards have multiple connectors (the BNC
for 10base2, a 15-way D-shell connector for an external transceiver, an RJ
jack for connection of UTP cable) and the card/s is/are not set up to
communicate through the BNC.  Some network cards are auto-detecting, others
(early ones) need a helping hand in the form of their setup programmes.
b) the card/s may not be properly configured in terms of I/O address and/or
interrupt address
c) the tcp/ip configuration may be faulty -- for example, incorrect mask
values, identical IP addresses
d) one of the cards might be faulty.

Suggestions:
a) on each of the two PCs, see if they will ping themselves.  For two PCs
set up as 10.0.0.1 and 10.0.0.2 for example you should be able to "ping
10.0.0.1" the first one and get a valid response.  If this is unsuccessful
then investigate the local hardware aspects (faulty card, bad IO or IRQ
values.)  Of course substitute your proper IP domain values here rather
than the example 10.0.whatever
b) run the cards' setup programme(s) and make sure that the BNC connector
is selected as the signal source, or choose auto-detect.  Run any card
diagnostics at this time to check the card/s functionality.
c) connect the two PCs together using a few metres of correct 50-ohm co-ax
cable, tee pieces and terminators and then from one machine, try to ping
the other one.
d) if you must use the hub in your final configuration, connect it in
between the two PCs and repeat the ping-ing to verify that all is well.

Now you should be ready to try more adventurous things, being reasonably
confident that the hardware aspects and first couple of ISO layers are
working for you.

Hope this helps,
Denis