DIY XLR ethernet cable audio snake on standard (unshielded) Cat5 Cat5e Cat6 cable

This document focuses on implementing balanced analog audio over UTP cable, getting 3 balanced channels.  

Commonly advertised solutions demonstrate 4 channels of XLR analog audio on a single Ethernet wire, but to have these work properly, you are required to use shielded Ethernet cable (STP) to properly work, specifically to maintain grounding.

STP is a bit more specialized and not always readily on hand.  

The construction method discussed in this post uses regular (unshielded) ethernet cable, know as Unshielded Twisted Pair (UTP) which can give you THREE (3) analog audio channels while simultaneously maintaining a common ground to all connections.  

• Get 3 balanced analog audio channels on Cat5/6 Unshielded Ethernet wire
• Works with phantom power
  
• Clearcom type systems
• Audio is clean, no buzzes, no hums, no distortion, no latency  
• Solid or stranded core (stranded less prone to breaking if coiled often)
• 1000+ foot distance is possible.

The main differences between UTP and STP Ethernet cable for Audio are the number of channels

1. Three channels vs Four.
   UN-Shielded Ethernet lacks an additional wire allowing for a 4th channel.
   
   
2. COST and AVAILABILITY
   UN-shielded Ethernet is inexpensive and found everywhere 

But we need the shield for audio quality in an XLR cable?

No, not really. Balanced audio primary rejection to interference result from the positive (in-phase) and negative (out-of-phase) relationship of the analog signal as it travels together over a cable pair.  The ground wire helps reduce unwanted noise and interference, and the shield (usually metal foil) found in some balanced mic cable provide rejection enhancement.

Click for Balanced audio in Detail

Solution A - TWO (2) channels using unshielded ethernet cable.

We can easily just connect an XLR pins on either end of the Ethernet wire and get 2 channels of audio.  XLR uses 3 wires for channel, and Ethernet has 8 wires, so that will easily get us 2 channels as shown in this diagram.

XLR over Cat5 using standard wiring methodology (2 unused wires)

Solution B - THREE (3) channels using unshielded ethernet cable.

In this example each positive and negative wire is connected to orange, green or blue.  But now the ground wires are all going to the same brown wire on either side of the Ethernet cable.  This is how you get 3 channels of audio when you only have 8 wires, when you normally would need 9.

Wiring Diagram

In this diagram, the brown/white stripe wire is being used for common ground for all the mics. 

In this example, the extra brown wire can bei either be ignored or attached together with the the brown/white wire to double it up.

Channel 1 blue pair 

Channel 2 Orange Pair 

Channel 3 Green Pair 

Ground Brown pair 

SHARED GROUND FOR ALL 3 CHANNELS

A variation is assigning one channel its own dedicated ground wire as you have two to use.

 SHARED GROUND FOR 2 CHANNELS and 1 CHANNEL DEDICATED

Useful if channels are going to a different location or you hare having a ground hum being introduce by a connected device.  You can have 1 channel isolated from the other two.

Implementation methods

Here are a few termination examples that could be used, but with an understanding of the wiring diagram, there are many possibilities that could be explored.

An efficient no soldering way to build pigtails using an RJ45 breakout box connected to the XLR connectors.  The one shown is a "female" adapter.

Use standard Ethernet cable with RJ45 ends to link each end of the snake.

In the wiring diagram below note that considerations for the "split pair" wiring that a properly built RJ45 Ethernet cable needs to follow.  Connect the Positive, Negative and Ground wires from each XLR connector to the terminal adapter according to the diagram shown.

IMPORTANT!!! "Hey, why is channel 2 wires not seem to be in order in this picture?"

There is an important wiring methodology that needs to be considered when using Cat5 cabling.  A properly built RJ45 Ethernet cable uses pin groups of  

ORANGE PINS: 1 & 2

GREEN PINS: 3 & 6

BLUE PINS: 4 & 5

BROWN: PINS 7 & 8

Here's a closeup

In this example, the RED XLR cable, made up of a red, white and ground wire, are going into pins 1&2 in the adapter

The ground wire (black shrink wrap) is going into pin #7.

Possible Applications

Send audio through preexisting Ethernet infrastructure allowing connections between locations allowing analog signals via the in house wires.  

Must NOT pass through any electronic equipment, direct patching between patch bay ports is ok.

In a situation that use this method all the Ethernet jacks were patched directly by IT staff.  Essentially a super long Ethernet wire cable, but not limited by the Ethernet length of 300 foot normal limitation.  A 1000' or more long connection in many cases is achievable.