Configuring the LF side of a NExT as FDX

I got a cat for my mom. She’s not chipped yet (the cat, not my mom…) So I need to chip her and register her in the local Finnish lost pet registry.

I figured I may as well implant her with something a little less stupid than the usual run-of-the-mill FDX chip. An xBT comes to mind, for functionality (although given that she’s quite a petite cat, the temperature thing might not be so accurate), or a NExT (although my mom and I would be the only ones to even think of bringing a cellphone to read something off a cat, but hey… why not).

Can the LF side of the NExT function okay at 134 kHz?

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Imma tag @Thebys as I know they where playing with fdx.


Yeah, the T5577 is a very universal beast, I actually have LF side of my NeXT programmed as FDX-B most of the time. I used Proxmark3 RDV4 to program it, because its antenna can be switched to 134 kHz which I think may have been a problem. Took a few tries to figure it all out, but works fine ever since.


I guess I’d recommend to program and test the implant before application because cats are not known for their patience. The FDX readers usually have a very strong field, way stronger than the Proxmark, so the NeXT deep in my R0 reads fine even from 3 cm distance.

xBT was sold out in the time of my last order, so I have yet to try that one, but I do hope to see temperature sensor NFC implants. 134 kHz has its drawbacks…


Ok great to hear it work!

Yeah I know T5577s are very versatile - and very easy to brick also. I was more worried about the NExT’s tank’s tuning. Apparently it’s not much of an issue.

And yes, if I do this, I plan to program both the LF and HF sides before injecting it into the cat, if only to avoid stressing the poor thing, but also to avoid getting a bunch of scratches onto my arms :slight_smile:

As for xBTs, I have a bunch of genuine Destron Fearing Bio-Thermo chips here, so it’s not an issue.

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yep… in fact i got iceman to put the fdx bulk programmer script together… remember that? anyway its in the iceman firmware.

Yeah I do recall. But like I said, I wasn’t sure the antenna itself lent itself to it.

ah I see… well for the most part when it comes to LF chips with high capacitances, the difference between 125kHz and 134kHz tuning … its virtually the same… sure there might be a tiny bit more performance for FDX-B if tuned for 134kHz, but honestly with an animal chip scanner it’s going to pick it up just fine. My halo animal scanner reads T5577s in FDX-B and EM mode super easy.

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Yeah that’s what I figured. I mean logically it ought to work. But hearing that Thebys actually rocks this in real life is better. That’s where the added value of the forum lies :slight_smile:

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Don’t animal chips need the parylene coating to discourage migration in their loose fascia? The NExT has no such coating so I’m not sure it would be good to put in an animal. I would ask your vet about that one. I also wouldn’t recommend injecting your cat yourself as you implied, kind of fucked up to be honest

That’s true, that. But the NExT is just one option. The Destron Fearing has the coating, if the NExT isn’t an option. The latter is a bona fide animal implant after all.

I very much doubt the vet will have any useful opinion on the matter, anymore than a human doctor would be of any help if you asked them what the best DT implant would be.

Also, I have no intention of doing it myself. I only experiment on myself and on individuals who are fully conscious of what they’re in for, and pets don’t fit in that category.

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I disagree, vets regularly implant microchips into their patients, whereas human doctors don’t. It’s kind of a strawman argument to assume that they would have no useful scientific opinion on the matter of chip coating and animal tissue/anatomy.

It was this statement that implied you wanted to implant your own cat, who obviously can’t consent.

You misread what I wrote: what I meant was that I had no intention of holding a freaked out cat against a Proxmark to program a blank NExT. I would program the chip before handing it over to the vet.

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As someone who regularly vaccinates my own pets, I suspect it is less stressful for the animal if I do it than taking the animal to the vet.

I’ve also had to give a dog subcutaneous saline before and anaesthetized macaws.

As far as I know most animals chips have a coating to encourage them to bond in place to reduce migration. Unfortunately a lot of the animal chip distributors in the US only sell to vets so that everyone gets their cut.

That may be what you meant but that’s not what you wrote. Glad to hear we’re on the same page regarding animal consent, though

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Of course

there is the possibility that Rosco could already be qualified, or getting a qualification…

as an example


The criteria for individuals wishing to apply for CANZ implanter status are:

1. A veterinary clinic or a qualified veterinarian.

2. A diploma (or higher) qualified veterinary nurse.

3. An implanter who has completed a recognised microchipping course.

4. An organisation who uses an implanter that meets the above criteria.

I have also considered doing this course as a favour to somebody, but the animals they bought came already chipped

Further details


  1. Read the Animal Microchip Implantation Best Practice Guide. This can be used as a study guide for those wishing to train to become CANZ-certified microchip implanters.
  2. After familiarising yourself with the Animal Microchip Implantation Best Practice guide, take the Microchip Implanter Assessment. The Microchip Implanter Assessment consists of 10 of multiple-choice questions. You must get 100% on the test in order to become a CANZ-certified microchip implanter. You may take the test multiple times if required to get 100%.
  3. After achieving 100% in the self-assessment test, you should perform microchip implantations under observation of a veterinarian to obtain a recommendation of proficiency from that veterinarian. Please note the following
  • You will need to perform two microchip implantations observed by the veterinarian to obtain a recommendation. These implantations may be performed directly one after the other, or on separate occasions.
  • Depending upon your level of experience and confidence, you may need to observe microchip implantation with the veterinarian (or other appropriate professional) prior to performing implantation yourself. You should determine what is most appropriate in consultation with your veterinarian.
  • Once you have satisfactorily implanted two microchips under observation by the veterinarian, the veterinarian will then be able to complete the Microchip Implanter Veterinary Certification, stating at the time of the microchip insertion demonstration the implanter was deemed to be competent.
  • CANZ recommends that any veterinarian providing microchip implantation training consult the Best Practice Guide and the associated assessment questions to ensure that they are aware of the knowledge and skill required to support an individual applying for CANZ approval.
  • Please be aware that it is the decision of the individual veterinarian as to whether they are willing to certify a prospective implanter’s proficiency and the cost they will charge for this service.
  • Part of the Microchip Implanter Veterinary Certification requires the veterinarian to confirm that you have access to a quality microchip scanner so you are able to scan microchips which you implant in the future. We recommend that you bring your microchip scanner with you to your veterinary observation.
  • Need to buy a microchip scanner? Information about purchasing a microchip scanner, and purchasing microchips, can be found here.

Remember, even Vets have to learn and carry out their first microchip implant at some stage…