Re: Network Wiring

On Wed, Jun 22, 2011 at 12:42 PM, Martin Maney <[email protected]> wrote:
> On Mon, Jun 20, 2011 at 01:23:23PM -0500, John Bundy wrote:
>> I think it would be safer to keep the high AC voltages associated with
>> ringing on landline phones away from ethernet:
>>
>> from http://www.derose.net/steve/guides/wiring/
>> *Warning:* When the phone rings, the voltage generates an electromagnetic
>> field, which in turn generates voltage in the adjacent Ethernet wires. S=
ince
>> Ethernet runs at about 2-5 volts rather than this 50-90 volts, conceivab=
ly
>
> I'll never argue against keeping the small signal wires away from the
> large-signal ones, especially not since the time Eric and I spent
> several days trying to repair a Data General CPU board (back when
> minicomputers were built from SSI TTL chips). =A0They hadn't warned us
> about this syndrome, caused by the on/off/lock switch which switched,
> on theoretically isolated poles, the AC and a logic line that ran right
> into the middle of the fifteen inch square CPU board...
>
> But the idea that 90V of very low frequency sine wave will produce any
> significant cross-talk in an adjacent twisted pair without a short
> circuit is silly. =A0Just sayin'
>

I will also point out that even if every single phone ring pulse
caused an error, the protocols running over the eathernet (802.11,
TCP, you tube?, kinda making this up..)  are designed to deal with
errors, and so the .whatever% of the time this impossible event
occurs, there will be a .dinky% hit to the bandwidth.   No one will
notice.

-- =

Carl K
-- =

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