RT-N66U Power adapter connector for POE

Discussion in 'Tomato Firmware' started by fiwiman, Feb 13, 2018.

  1. fiwiman

    fiwiman Connected Client Member

    I'd like to hook my RT-N66U via a passive POE injector (using the original 19v adapter). I need two adapters for either end, but I'm struggling to find a male barrel adapter connector that matches what this router has.

    I'd like to use my existing 2.1mm barrel passive injector but this RT-N66U uses non standard size and voltage...

    Edit: Just realized that you can find a 5.5x2.1mm female to 2.5x0.7mm male but it's practically impossible to find the reverse, ie: 5.5x2.1mm male to 2.5x0.7mm female...
    Last edited: Feb 13, 2018
  2. Monk E. Boy

    Monk E. Boy Network Guru Member

    You may have trouble if your switch tries to negotiate a 1Gb link, as that requires four pairs and won't always fail gracefully to 100Mb if there's only 2 pairs connected. If you can configure the switch to only negotiate 10/100 and not 10/100/1000 then this shouldn't be a problem.

    I haven't done the measurements but I'd be surprised if it wasn't on Digikey:

    The trick is getting inner diameter and outer diameter measurements. That is a damn small plug. You'd almost need a micrometer to get a good measurement.
  3. fiwiman

    fiwiman Connected Client Member

    Thanks for the help.

    I bought a Gigabit Passive PoE Injector which seems to work well with an older RT-N16 I had lying around and haven't noticed any negotiation problems as of yet, knock on wood....The injector does the more standard 2.1*5mm male/female barrel connector size, thus the reason why I'm using the RT-N16 instead of the RT-N66U.

    It would appear that the measurements are 2.5mmx0.7mm for the RT-N66U plug, I was able to find a "5.5x2.1mm Female to 2.5x0.7mm Male" adapter on ebay but finding the reverse is hard. I may need to make my own or something..
    Last edited: Feb 14, 2018
  4. Monk E. Boy

    Monk E. Boy Network Guru Member

    I think the WAN on the N16 was only 100Mb, the LAN ports were 1Gb.

    I suspect the measurements on eBay may be a little, uh, off. The sellers don't always know what they're selling and come up with odd ways of measuring things that then cause you to have trouble finding it someplace else. Possibly that's their intention, but I suspect ignorance of the material is at work.

    I just ordered a micrometer, after it shows up in a couple days I'll take a measurement for you. Maybe we can find a part at digikey or newark. They probably have it its just finding it that's the problem. I've been meaning to get one, you just gave me the excuse!
  5. koitsu

    koitsu Network Guru Member

    RT-N16 Ethernet ports (that means the LAN and WAN port -- they're all on the same physical Broadcom switch) are all 1000mbit (gigE). Dedicated LAN traffic will be at gigE speeds, however LAN->WAN or WAN->LAN traffic, due to NAT, routing, CPU speed/limitations, etc. can handle up to about 175mbit/sec throughput-wise, IIRC. CTF may improve that, but we all know the complications/downsides of CTF.

    I do miss my RT-N16 at times. Really solid and good router. Toastman would agree. :)
  6. Sean B.

    Sean B. LI Guru Member

    If you have any experience with soldering, replacing barrel jacks on PCB's is rather simple. The posts are rather large ( relative to the rest of the components on the board ) and easy to work with. Just solder in a matching jack for what you need.
  7. Monk E. Boy

    Monk E. Boy Network Guru Member

    I got my micrometer in last week... but before it came in the excrement hit the fan at work, and this week I'm covering for someone on a training session. I might have time tonight if I can get the fires down to a smolder.
  8. Sean B.

    Sean B. LI Guru Member

    A digital caliper would be more than accurate enough for a barrel jack, and much less sensitive to placement on a cylindrical object.. if you happen to have one.
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