I'm currently troubleshooting an environment where there is a lot of network latency issues, all sporadic and intermittent across workstations. The network uses a mix of calls from on-site dialer and traditional RJ11 phones working off of Vonage gateways. Lots of reports of call quality issues, bridging calls, one-way audio, etc.

I made some tweaks on their firewall which seemed to have helped somewhat, but looking at their cabling, I'm seeing most of the devices share single ethernet cables over split pairs (and not using splitters, just the individual pairs separated and spliced into multiple jacks or plugs). Some of these have a single cable split to x4 RJ11 phones or two pairs to a PC and the other two pairs split to two additional phones. Moreover, the cable sheath is cut back exposing more than 5 inches of unprotected pairs before they hit the jack.

I know bandwidth is diced up, but I'm led to believe this kind of mix of VOIP, POTs, and internet traffic all running over the same cable would lead to issues with crosstalk, latency (when all connections are in use), etc.

Question: does this non-standard approach to splitting ethernet cables have any affect on network communications quality? Would it cause symptom such as those I referenced?

  • I think it's safe to say that yes, that kind of cabling is highly likely to be the source of the issue.
    – Davidw
    Aug 9 '17 at 22:28
  • 2
    The whole point of cabling standards is to ensure signal quality at the rated speeds. Given your described state of that cable plant, I'd walk away from the job until the cabling was corrected. Aug 9 '17 at 22:39
  • This almost reads like the result of a do it yourself cabling job.
    – Davidw
    Aug 9 '17 at 22:43
  • You kind of answered your own question. The cabling certainly isn't helping. Aug 10 '17 at 3:15
  • I get the cabling is jacked up, I just wanted to confirm as I don't recall ever running into something like this in a business environment. Figured I'd at least get a second opinion.
    – mlxs
    Aug 10 '17 at 6:32

Toner is working sporadically and I'm guessing its because of crosstalk between wire pairs split between two jacks. I ran wire tests and had to replace about 6 jacks. Witnessed bridged audio between to phones which shared a common ethernet cable. Additionally, all the wire trunks were laying directly on top of lighting ballasts. Also found ethernet split and re-spliced with scotch tape! Pretty sure this violates all standards for cabling. Thanks for the assist!

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