Re: POTS and Ethernet over CAT-5 Cable

[Isaac Wingfield <isw@xxxxxxxxxxx>]

In article <q-2dnZ2dnZ2LDsvFnZ2dndFbYt-dnZ2dRVn-yZ2dnZ0@xxxxxxx>,
 "Dan" <Dbambach@xxxxxxxxxx> wrote:

> There is actually a lot of discussion about this in many engineering
> circles. The general consensus is yes, Ethernet uses two pairs, which leave
> two pairs left for another Ethernet circuit, POTS, audio, etc. The concern,
> from what I have read in blogs is if you were to add something to the two
> unused pairs that would create a high amount of energy (noise) that could
> bleed over onto the Ethernet pairs causing packet errors and retries slowing
> the link down, or even crashing it. A POTS line works fine except I have
> heard of the ringing cycle causing issues, but that was on a CAT5 and not
> CAT5-E cable.

You might take a look at the Ethernet spec, instead of just guessing; it
specifically mentions using one (or both) of the spare pairs for POTS
(or a second Ethernet). Why do you think they carefully avoided the 4-5
pair for Ethernet, when you can plug an RJ-11 right in there and use it
for a telephone?

Isaac