As you need signal GND in the other end one of the WHITE lines must be connected.
I normally connect all without issues however because of the different twisting of the pairs in Cat
5/6 the WHITE lines does not have the same length which COULD lead to hum loops.
And yes hum in theory could be an issue but with the wiring below it has not been a problem for me
the last 10+ years and I have run lengths way beyond 50 m big server rooms.
From: Sa¹a Stjepan Bak¹a [mailto:sasa dash stjepan dot baksa at os dot t dash com dot hr]
Posted At: Tuesday, May 19, 2009 6:32 PM
Posted To: Monowall
Conversation: [m0n0wall] console over modem?
Subject: Re: [m0n0wall] console over modem?
AC hum - that's true but difference in voltage level between two
locations can be so
significant that you can burn your equipment. Especially if you have
Jewell, Michael wrote:
> It should be noted that you should only ground one end of the cable, just like in balanced audio,
you could get some pretty nasty AC hum's if you ground both ends...
> From: Claus@Monowall [mailto:Monowall at mail dash fwd dot archie dot dk]
> Sent: Tue 5/19/2009 3:26 AM
> To: Wayne Fiori
> Cc: m0n0wall at lists dot m0n0 dot ch
> Subject: RE: [m0n0wall] console over modem?
> Normally I connect RTS, CTS, RX, TX as one conductor en each pair and connect the 4 other
conductors in the pair to GND.
> GREEN RX
> WHITE(GREEN) GND
> BLUE TX
> WHITE(BLUE) GND
> ORANGE RTS
> WHITE(ORANGE) GND
> BROWN CTS
> WHITE(BROWN) GND
> This configuration lets me run 115200 over 80m in normal server-room conditions.
> -----Original Message-----
> From: Wayne Fiori [mailto:dev9null at gmail dot com]
> Posted At: Tuesday, May 19, 2009 8:05 AM
> Posted To: Monowall
> Conversation: [m0n0wall] console over modem?
> Subject: Re: [m0n0wall] console over modem?
> Considering the difference in data rates and signaling, re ethernet
> versus serial, the wire pair twists are not important in the serial
> cable. They are important for ethernet however. But even at 9600 baud,
> a 15m cable is pushing the length limits.
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