On Sun, 30 Sep 2012 16:44:16 -0700 (PDT), klem kedidelhopper
wrote:

I have to install an Internet connection at a location somewhat
removed from the origination point. The building is very large, spread
out, and difficult to run wire through. Presently there already is a
connection terminated in an Rj45 at a point that is only used for one
week out of every year. All other times there is nothing plugged into
this jack but the connection remains active. In order to make the
connection to the new location about 100 feet away can I tap off the
existing jack and "daisy chain" the wire to the new location and then
terminate that wire in a second R45?

Yes. It's just an exension cable.

I know this is not common practice
but if only one computer is using the line at any particular time
would this work?

Yes, it will work with only one computah connected.

There will never be a time that two computers will
ever be operating on this line at the same time although for that week
in question they both may be plugged into it though. would this be an
issue?

Yes, it's an issue. Twisted pair ethernet is *NOT* a bus arrangement
as in POTS phone lines. It's a star. Just add a cheap 5 port
ethernet switch where everything comes together and you'll be fine.

I can arrange to have the new location unplugged during this
time if need be. Thanks for any advice. Lenny

No need with an ethernet switch.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558