Re: POTS and Ethernet over CAT-5 Cable

[Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx>]

Hello Brian,

> Is it possible to use some of the extra wires in CAT-5 cable to run a
> POTS line or two?  I heard that Ethernet only uses two of the eight
> wires.  Is this true?  If so, seems like I could run 3 POTS lines in
> addition to my Ethernet over my CAT-5 home network.

There will be a serious current spike whenever the receiver is taken off
hook or placed back. That may or may not cause packet losses on the data
pairs. Ringing can also generate 90V or so and an open loop phone line
can run up to such voltage levels as well. So if you accidentally
miswire something ... bzzzt.

Utilities also have their rules and some may not endorse such wire
mixing. Anyway, personally I wouldn't do it so I ran two CAT-5 to every
location from the central closet. CAT-5 is cheap. Plus now it's future
proof in case there comes a day when the other two pairs are being used
for the data link.

> If this is correct, are there any jacks available that would make this
> easier than cutting open my cables?  Thanks.

You have to cut the cables anyway to connect an RJ45. In this case you'd
just have to cut the sleeve back some more. But again, I wouldn't do it.

Regards, Joerg

http://www.analogconsultants.com