10/100 Base T Splitter Adapters
Last updated: 8/20/03
luck" recently posted the following
question in our
is the best and hopefully cheapest way I can use two computers
"Radioshack has a Y network cable splitter but I presume
you can only use one computer at a time."
This question has been posted in our forums a few times,
so I decided to take a closer look.
10/100BASET Ethernets only use four of the eight wires in
a CAT5 cable. T Splitter Adapters (also known as Modular
adapters) combine two RJ45 8-wire Ethernet jacks (ports)
into one 8-wire jack
and split them apart at the other end.
Most of the splitters I've
seen are spec'd for 10BASE T. ATS, Inc. says their's are
rated CAT 5e and claims they will
work with 100BASET: "The
ATS 10/100 Base T Splitter Adapters convert one RJ45 4-pair
Jack into 2-pair Jacks while still maintaining 10 and 100
Base T system performance. The use of this adapter will allow
two 10/100 Base T HUB ports to function on one horizontal
cabling run (minimum 2 adapters required), we will include
one 2" Patch cord."
I asked ATS for a couple of their
T-splitters for testing. They arrived the other day. Of course,
I had to take one apart to see what makes it tick. I didn't
see anything unusual inside, such as as extra
the jack. In fact some of the pairs are untwisted more that
the half an inch specified for CAT5/5e jacks, plugs, and
patch panels. (The jack contacts in the below picture are actually
To test the units, I used them to connected
two computers at each end of a single CAT 5e cable running
my shop in a converted garage
to my Wife's office at the other end of our house, or about
120 wire feet. I had the
computers at one end simultaneously send files to
at the other end. Each sending computer and the corresponding
computer receiving the files at the other end were on an
than the other sending a receiving pair.
The only things
in common between the two networks were the
T-splitters and the long cable. I measured how long it
took one computer to send the Windows 98 upgrade cab files
files, 91.5 MBytes, while the other computer at the same
end was constantly sending files. I then removed the
and a computer at each end and sent the cab files again
over the same cable. The time, 20 seconds plus or minus a
(which is about as fast as the computers can transfer data
given the Ethernet and operating system overhead, and disk
drive speeds, etc.), was the same in both cases. So, using
data streams resulted in no slow down, and apparently no
data corruption from interference, which would have resulted
packet retransmissions and slower rates.
Conclusions. The ATS T-splitters
work as advertised. You can use two computers at the same
time on the same line without any noticeable
degradation. If you search google.com with "t splitter,"
you should find them. Larry
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