RJ-45 & RJ-61 does have different pins termination. Straight-A, Straight-B, Cross-Over (A & B each end) for RJ-45 (Data). Paired at middle going out method meaning 4 & 5 pin + 3 & 6 pin, and so on for RJ-61 (Voice).

In Cat5e (Data) when you do not follow Straight-A/Straight-B crimp method. The signal may not reach 100m if you used something else.

Since RJ-61 (for Voice) is a different pins termination, I use CAT6 instead.

Here's where I'm not sure though...

Is CAT5e inferior over CAT6 because of structure when you use RJ-61 termination (Voice)? Or is it actually better?

  • Network cabling uses 8P8C connectors. The RJ connectors are for voice. You must use the same category parts in the entire cable channel, and have it pass the test suite for that category, to be able to call it a particular category. By the way, Category-5 has not been valid in this century. It was deregistered in 1999, replaced by Category-5e.
    – Ron Maupin
    Nov 2, 2017 at 0:04
  • thanks i'll focus my question on CAT5e then, will edit question. Nov 2, 2017 at 0:07
  • For network cabling to pass a category test, you must use a T568A or T568B 8P8C connector. RJ-45 connectors are keyed connectors for voice, and RJ-61 connectors are also for voice, but RJ-61 connectors separate the individual wires in a pair too much to be used for data. I really don't understand, "the added protection features CAT6 have over say CAT5e." There are differences in the test parameters, but nothing about protection.
    – Ron Maupin
    Nov 2, 2017 at 0:12
  • Seriously, if you are asking this question, I doubt that you could install Category-6, even with all Category-6 parts, and have it pass the test suite. Even experienced installers can have problems with Category-6 and Category-6a.
    – Ron Maupin
    Nov 2, 2017 at 0:15
  • Omitted protection, I do Data cabling using CAT5e & CAT6. Voice is new to me however, and I already have cables running for voice, some are 2pins and new office where CAT6, I need to replace 2 pin with a 8 pin cable but I only have boxes of CAT5e available. Hence the question. Nov 2, 2017 at 0:26

2 Answers 2


Data (ethernet) uses pair-wise 1/2, 3/6, 4/5, and 7/8. Your voice wiring -- 4/5, 3/6, 2/7, 1/8 -- creates split-pairs. That's why it doesn't work well for data. The category rating of the cable (which is a measure of attenuation, frequency, and cross talk) won't make any difference if the differential signal is riding different pairs.

  • Yes this is what I know as well. So it's a complete No-No to use CAT5e using RJ-61 termination for Voice? Do you have any links supporting it? Nov 2, 2017 at 1:16
  • @AlvinCaseria, I think Ricky and I are telling you that you cannot use it for data, but for voice (POTS) it should work. If by voice, you mean VoIP, then that is really data, and it will not work.
    – Ron Maupin
    Nov 2, 2017 at 2:03

What really matters is that you use the same category components throughout the cable channel, and the resulting installation passes the category test suite. You cannot mix and match different categories of components, or use unregistered components, e.g. your RJ-61, and claim a particular category. The standard you must meet is ANSI/TIA/EIA 568 Commercial Building Telecommunications Standard.

You also need to follow the ANSI/TIA/EIA Commercial Building Pathways and Spaces, along with the various laws, rules, and ordinances required by your AHJ. The least is usually the NFPA 70, the National Electric Code (NEC), but your AHJ may have more stringent requirements. Failing to do this can get you fined and have your building red-tagged for occupation until the problems are corrected. There is also the threat of criminal prosecution in the case of something like a fire where anyone is injured or killed.


Based on you comment, this is for voice (POTS) cabling. There is no distance limitation or test suite for POTS cabling, which is usually Category-3 cabling. Remember that the telco uses Category-3 copper cabling to get from the CO to your site, usually several miles away.

The current best practice is to install all UTP cabling in a data category. That way the cable plant can be used for both voice and data. Trying to install and maintain two separate cable plants is expensive and confusing.

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