Wiegand control board throws error with NeXT

When adding the RFID code to the system I get this error:


Is there a way to change the code on the chip to allow it to work? Do I use the NXP Tagwriter?

Thanks, everyone!

You can only change the code on the LF side of the NExT (125kHz). The HF side (13.56MHz) does not have a changeable UID. What type of system are you trying to add your NExT credentials to, and is it looking for the LF or HF side?

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Hello Satur9 - Wiegand 26 control board with 125kHz reader so LF

I personally haven’t seen that info message before, but hopefully somebody else has that can confirm my ramblings below.
The following is just my best guess :salt:

TagWriter, TagInfo, NFC tools etc only “talk” to the HF side of you NExT.

Obviously you have tried to enroll it, which is probably the best way assuming it is the same mode as your system,but, either way it looks like your LF side T5577 chips UID is outside of your systems parameters
Your NExT T5577 chip comes Pre-programmed in EM41xx mode with a 40 bit unique ID, so I am not sure if your system is running EM but your UID is outside what it is looking for or if the system is actually running in HID, Indala ProxCard etc… mode.

(you could maybe do some more fault finding, like getting more info on the system, scanning your authorised card to see the UID, scanning your NExT on a reader to see if it at least shows its UID (maybe what you tried and got the info message)
Either way, unless your system has a writer that you could write to your NExT, which I highly doubt (it probably is just a reader that reads a preconfigured new card/fob to then enroll it in the system)

So I think :bulb: : your best bet from here is likely a Proxmark (You might get away with a Blue cloner, but the Proxmark is probably the better option ) And the ProxMark3 Easy is a happy medium between the RDV4 and Blue cloner.

Definitely doable, but sounds to me at least, unfortunately you have one last hurdle.

Keep us in the loop, I hope that all makes sense.
Ask again if you need clarification.

Also I’m happy for somebody else to chip in if you have another suggestion that may be easier

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Thanks for the help. I tried to enroll the chip by directly reading it into the system using the dangerousthings reader and got the displayed error. I will try to scan it on the door reader itself and see what shows up because it might be a different number or reading that will actually function. Maybe it will truncate the number on the reader and be happy? Who knows. Getting into the office was a big hope for my NeXT so hopefully I will get it working. My girlfriend and I are buying a home next year and I do plan to put RFID readers all over the house so at least then it will be very useful.

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Well there’s your problem! The KBR1 is HF.

Yep, theres your solution! There are many different ways to interpret the same 1’s and 0’s. If you scan on a door reader, then look in the logs to see if it has the number of the unauthorised tag you should be able to copy it from there.


I’ve successfully enrolled the LF side of my NExT into 3 UHPPOLTE Weigand 26 controllers now, each time by doing a direct read on the door readers. I have EM type USB readers on the system management computers but they’re generic readers and I found they have issues reading the T5577 chips in general. So the door readers work and each controller actually displays a different ID number from the NExT which I think is pretty cool too.

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I just enrolled myself today using the UHPPOTE wiegand 26 controller and compatible reader. Worx!
Thanks, everyone for your input on this. Kdude0 thanks for the confirmation it also worx for you too.


You’re welcome, I’m glad it’s working for you :+1::grin:

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