On 6 Jan 2002, at 14:29, David Hurst wrote:

> I want to network teo home computers.  Each has a NIC with two
> types of connectors,, a BNC and a RJ45  i think they are called.
> The computers are about 80 feet apart.  One running Windows XPl;
> the other Windows 95. What is the best type cable to network them,
> the BNC type ot the RJ45 type..???   Which is best got
> reliability, and for speed, at that distance..???
>
> thanks
>
> David Hurst


  The NICs that you have are "combo" cards, which have one set of
badic network circuitry, but two "transceivers" corresponding to two
different 10Mbps Ethernet standards, 10-Base2 (BNC co-ax) and 10-
BaseT (RJ-45 Cat-5).  Note that such cards usually only have one
transceiver or the other active at any given time -- depending on the
manufacturer and model, this may be controlled through the network
control panel, or there may be a setup program on an accompanying
floppy to set this.

  I prefer Cat-5 cabling for most purposes, because it (a) can
support 100Mbps operation if you someday upgrade to better NICs, and
(b) generally (I'll get to that in a moment) makes it easier to add
more nodes to the network.  Specs limit cable runs of this type to
100 meters, which is about 325 feet, so 80 feet is no problem.  Cat-5
cable is, however, not built to withstand quite such rough treatment
as some people subject it to.
  Cat-5 cable is normally used with a hub or switch -- or some
combination of them -- at the network's core, and additional machines
can be plugged into this piece.  However, if you never expect to want
to add a third PC, you can get a Cat-5 "crossover" cable that
directly connects the two NICs.  This is the exception I hinted at
earlier.  Ready-made crossover cables longer than about 15' are
fairly rare, though, so finding one to span 80' could be a challenge.

  Co-axial cable offers two main advantages over Cat-5:  (a) it's
more robust, shielded from electrical interference and better able to
withstand a certain amount of rough treatment, and (b) cable runs can
be up to 180 meters, about 500'.
  Note that although it is physically possible to screw the cable
ends onto the NIC connectors, this will not provide a working
connection.  For each NIC, you need a "T" connector -- the stem of
the T goes onto the NIC connector, and the cable connects one side of
one T to one side of the next.  A "terminator" resistor goes on the
unused sides of each of the end Ts.
  Note that you can find both 50ohm and 75ohm terminators; Ethernet
uses 50ohm.  (The 75ohm variety are used in some video applications.)
There are also two kinds of T connectors:  the oneds that look like
they're machined from solid metal are rated for 75ohms, and the ones
that look like they're formed out of sheet metal are rated for 50ohms
-- but since they're just conductors, either variety should work.

Dave Gillett

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