I have two Cat 5 cables pre-installed in the walls. I need to connect two rooms, each room has its own set of in-wall Cat 5 cables and a slots. Does it work to use a Cat 6 cable to connect the two rooms (using the slot in each room)?

  • I dont see any problem using a CAT6 cable to connect the two rooms.
    – user36472
    Commented Nov 12, 2018 at 8:15
  • The point is the rooms are pre-equipped with CAT5. So basically, CAT6 will act as a connector between two CAT5s. Is that OK? Commented Nov 12, 2018 at 8:43
  • 2
    As long as the maximum length of the cable doesn't exceed the recommended 90 meters i can't see any problem doing so.
    – user36472
    Commented Nov 12, 2018 at 8:48
  • Actually, you are supposed to have the permanent cable in the wall, which will be solid-core cable, then you are allow one stranded cable on each end to do the connections to the equipment on each end. You do not have a cable connecting two horizontal cables (wall-plate-to-wall-plate) like it sounds like you want to do. Splices, taps, couplers, etc., are not allowed in a cable run.
    – Ron Maupin
    Commented Nov 12, 2018 at 15:28
  • 1
    I'd be surprised if the ports in the rooms don't end up in panel in a closet somewhere in your basement, where you only a need few inches of cable to go between ports in the panel. Even better if you put a switch there. Commented Nov 12, 2018 at 18:01

2 Answers 2


A short answer is absolutely; CAT6 is backwards compatible to CAT5.

The full answer; since CAT ANSI ratings for cables describe the quality of the wires and speed/attenuation rating of the cable, and NOT the connectors and pin-out of the cables, "Not necessarily".

It sounds like you are using cables with RJ-45 connectors. Usually people refer to these cables as "Ethernet" cables, although Ethernet is a layer 2 networking protocol and not a type of cable. I'm going to infer that you have networking jacks in each room with a punchdown block for these RJ-45 connectors, and that they are 8p-8c. Assuming all this, because your question was about the rating of the wires within the cables, and not in regards to the pin-out on the ends of the cables, the correct answer is "Maybe!". For example, if the jacks in the wall are pinned out in in a non-TIA configuration (neither 568A or 568B), you will not be getting a usable signal over the connection. While an unlikely scenario it is certainly possible; it is worth understanding the CAT rating of the cable is not the only relevant factor in determining your cabling success or failure.


Yes. Cat-6 cable requirements are a superset of Cat-5e - there's no problem.

Note that a length of Cat-6 doesn't make the full path Cat-6. ;-)

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