Re: [Linux-decnet-user] Well, i think i need help :)

[Paul S. <psh...@st...>]

At 14:38 31/10/01 +0000, Steve Whitehouse wrote:

>You should be able to find some thick to thin ethernet convertors if you
>look through second hand computer part suppliers. I doubt you'd find any
>being sold new, certainly that kind of thing used to be quite expensive
>I think.

This guy has a thick Ethernet setup. His ethernet cable will have some
transceivers tapped into it, and he needs to connect his newer computers to
one of these using a transceiver cable. PC cards supporting an external
transceiver interface are rare nowadays, but many old cards had them as
standard, including the original Novell NE2000. Most people will have one
in the junk box - I've got dozens (but I don't live in Bosnia). It's a 15
pin connector similar to a PC joystick port.

It's a professional job to attach new taps to thickwire ethernet, but you
could connect an 8 port switch to an existing tap using the AUI interface
on the switch (though cheap switches don't have an AUI interface nowadays).

It's possible to get adaptors which allow you to unscrew the terminator
from one end of the thick cable and attach a BNC connector. These were
never part of the official ethernet spec but work well enough (though the
whole point of thick ethernet was reliability - users couldn't disconnect
the segment terminator, and you could drive a tank over the cable itself).
Tandy used to sell them, and they may still be in the Radiospares catalogue
- usually they're marketed as RF adaptors rather than Ethernet adaptors,
but if they're 50 ohm impedence with the correct connectors they should work.

Alternatively, the old kit could all be cabled up with 10baseT cabling
using 10baseT transceivers. These are very small and plug straight into the
AUI socket without a transceiver cable. They used to be quite cheap (<US$50
each) but are less common now and may cost more. Again, I have 2 in the
junk box!

Electrically thickwire ethernet is exactly the same as 10base2 ethernet,
except that the cable has much lower signal loss so each segment can be
much longer (1Km? 500m? I can't remember without looking it up).

HTH, Paul


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