VoIP and 2-pair Cabling

Unanswered Question
Dec 11th, 2008

On Cisco hardware:

Can VoIP be hosted using only 2-pair of wires of a Cat6 cable?

If so, are there any disadvantages to doing this when compared to using all 4-pair in a Cat6 cable?

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Overall Rating: 4.5 (2 ratings)
Nicholas Matthews Fri, 12/12/2008 - 12:58

Ethernet will not run on 2wire cable.

If you're running analog telephony cable, then yes. I currently have 4 analog phones running out of a split Cat5 cable at the moment.

I don't think there will be any difference, but that isn't definitive on a electrical basis. I wouldn't expect for there to be any difference.

Rob Huffman Fri, 12/12/2008 - 13:28

Hi Steven,

If you are planning on doing this for an Enterprise deployment it's probably not a great idea. If you are doing it for testing or labbing something up then I would go ahead and give it a try. The characteristics of Cat5 or Cat6 are such that trying to "split" the cable for two devices will likely introduce many unwanted results. Cross-talk being near the top of list.

One other thing to keep in mind is that Gig 10/100/1000 uses all 4 pairs of the cable.


Hope this helps!


steven.e Mon, 12/15/2008 - 04:35

Thank you for the response. I found it and the link very helpful.


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