On 15 Mar 99, at 19:13, Bruce Boschek wrote:

> In <[log in to unmask]>, on 03/15/99
>    at 06:51 AM, Michael Beechey <[log in to unmask]> said:
>
> >Dear Friends,
>
> >I'm putting together a small network, for classroom use, no essential
> >data transfer, maximum distance to hub 5 meters ( about 15 feet), using
> >cheap NE2000 clone cards, 15 machine max.
>
> Michael,
>
> Coax and BNC connectors seem to win hands down in this kind of a
> situation.

  In a business or home setting, I'd agree.  In a school setting, the
difficulty of diagnosing co-ax problems looks pretty daunting, and the
ability of one mischief-maker to break the entire net -- perhaps even
by accident -- is just not acceptable.

> You can take a machine off line or put it back on again without
> causing any problems on the network ....

  But you cannot add more machines (connectors) to the network without
knocking everyone off-line.

> You will only need a single crimping tool to attach the BNC
> connectors.

  On a large network with a dedicated operations staff, you can save some
money by buying cables and connectors in bulk, and using a crimping tool to
make your own cables to exact length.
  This takes time.  There are restrictions to follow -- for instance,
connectors should not be closer together than 6'.  And on a network of
15-20 machines, I don't believe you save on the cables much more than
the cost of the crimping tool.  So I recommend buying co-ax cables,
with BNC connectors already attached, in 6', 9', 15' and 25' lengths,
as needed (plus a few spares).


> Twisted pair can be made to allow higher data-transfer rates, but if
> understand your requirments this will be of no notable benefit to you.

  Twisted pair can be sped up in a couple of ways, but I agree that that's
unlikely to be needed in this case.

> On top of it you will need much more "equipment," a wall socket for
> each machine,

  There is no requirement that twisted-pair cables run inside walls.

> transciever cables,

  The vast majority of 10Base-T NICs include the transceiver built in --
raw AUI connectors have become rare.  Cat5 patch cables with RJ-45 on
each end do the job nicely.

> a hub

  That's true, for more than two machines, twisted-pair needs a hub.
Hubs up to about 16 ports are not that expensive, though -- my 9-port
hub was $35.

> and diverse connectors and crimping tools,

  See my comments above about co-ax crimping and transceivers.

> plus a bit of testing equipment if you don't want to have lots of
> headaches.

  90+% of twisted-pair problems affect only a single station, and you can
apply tools to the link to that station to diagnose the problem.  Co-ax
problems tend to take down the entire network, and so unless you've shelled
out big bucks for a TDR, there isn't much in the way of tools that can help.

> I run a thinnet coax network here at home, have 6 or more machines

  So do I.  But it's not what I would recommend for classroom use/abuse
without a dedicated network staff, and I'm gradually switching over to
twisted-pair.  [The $35 hub referenced above offers 8 10Base-T ports
and one BNC, so I can use it to migrate.]


David G

            Do you want to signoff PCBUILD or just change to
                    Digest mode - visit our web site:
                    http://nospin.com/pc/pcbuild.html