You could terminate the existing end with a standard RJ-45 male connector,
then purchase a RJ45 female to female connector. Then run a standard patch
cable the rest of the distance.  If you do a good job of terminating the
wires and don't abuse the distance, you should be fine.
http://www.connectworld.net/cgi-bin/iec/RJ4508F-F-MT  HTH, Anthony

>
> In my office, we have to relocate 2 network points to
> another room where the existing cable can't reach the
> new point. I think, it requires additional 15 meters.
> I just want to know whether it's possible for me to
> just soldered additional cable to the existing one to
> make up the additonal length without losing much
> signal.
>
> It's quite difficult to lay new cables from the
> existing switch without engaging a cabling vendor.

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