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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Lighting Forum => Topic started by: David Allred on April 29, 2019, 02:49:19 PM

Title: Doubling up on Cat5e pairs for security with DMX?
Post by: David Allred on April 29, 2019, 02:49:19 PM
Beyond redundancy, is there a benefit to tying (for ex) green & orange together and green stripe & orange stripe together.  Or perhaps, is it bad for some reason.  Gain or loss of max distance?

Can Green & Green stripe be tied for +data and Orange & orange stripe be tied for -data?  I say no.  Am I right?

Thanks,
Title: Re: Doubling up on Cat5e pairs for security with DMX?
Post by: Mac Kerr on April 29, 2019, 03:15:59 PM
Quote from: David Allred on April 29, 2019, 02:49:19 PM
Beyond redundancy, is there a benefit to tying (for ex) green & orange together and green stripe & orange stripe together.  Or perhaps, is it bad for some reason.  Gain or loss of max distance?

Can Green & Green stripe be tied for +data and Orange & orange stripe be tied for -data?  I say no.  Am I right?

Thanks,

GN/GW and OR/OW are twisted pairs. That is where your noise resistance and signal integrity comes from. DO NOT use GN+OR and GW+/OW as the 2 conductors of a pair, it will not be a twisted pair and will not have the advantage of using twisted pair for signal integrity. I see no advantage to doubling up conductors as there is very low amperage involved so very small conductors are fine. Unless the cable is specified as low skew doubling up conductors may degrade your signal quality by having slightly different lengths causing a smearing of the data.

Mac
Title: Re: Doubling up on Cat5e pairs for security with DMX?
Post by: David Allred on April 29, 2019, 03:22:27 PM
Quote from: Mac Kerr on April 29, 2019, 03:15:59 PM
GN/GW and OR/OW are twisted pairs. That is where your noise resistance and signal integrity comes from. DO NOT use GN+OR and GW+/OW as the 2 conductors of a pair, it will not be a twisted pair and will not have the advantage of using twisted pair for signal integrity. I see no advantage to doubling up conductors as there is very low amperage involved so very small conductors are fine. Unless the cable is specified as low skew doubling up conductors may degrade your signal quality by having slightly different lengths causing a smearing of the data.

Mac

Best possible answer.  No extra work.  Single twisted pair it is.

thanks
Title: Re: Doubling up on Cat5e pairs for security with DMX?
Post by: Tim McCulloch on April 30, 2019, 11:23:39 AM
Quote from: Mac Kerr on April 29, 2019, 03:15:59 PM
GN/GW and OR/OW are twisted pairs. That is where your noise resistance and signal integrity comes from. DO NOT use GN+OR and GW+/OW as the 2 conductors of a pair, it will not be a twisted pair and will not have the advantage of using twisted pair for signal integrity. I see no advantage to doubling up conductors as there is very low amperage involved so very small conductors are fine. Unless the cable is specified as low skew doubling up conductors may degrade your signal quality by having slightly different lengths causing a smearing of the data.

Mac

It will also change the capacitance of the cable.

Title: Re: Doubling up on Cat5e pairs for security with DMX?
Post by: brian maddox on April 30, 2019, 11:29:10 AM
Quote from: David Allred on April 29, 2019, 03:22:27 PM
Best possible answer.  No extra work.  Single twisted pair it is.

thanks

Oh that far more internet exchanges could go this well.

OP:  Should i do the thing?

Answer:  No, because *Informed Reason 1 and also *Informed Reason 2.

OP:  Okay, I won't do the thing.

I feel like i've just witnessed a Unicorn Sighting....