Low Frequency and High Frequency RFID?

Not sure which category to place this under, but I came across something interesting while messing with my phone’s NFC capabilities and the RFID diagnostic card. My smartphone has a payment service enabled, and I’ve payed before using NFC. I placed the RFID card on the back of my phone, and it glowed red, indicating that the phone had HF capabilities. However, if I just opened a card up as if I were paying on the lock screen and signed in, the RFID card glowed green, showing that it was communicating on the 125 kHz frequency. However, all of the articles I’ve found online just talk about the NFC, which inherently uses high frequency. Anyways, just thought I should share!

For the specs:
Phone: Samsung Galaxy S20

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Samsung phones also have a magstripe emulator that functions in the LF range, this allows them to simulate a card swipe and work at terminals without NFC capabilities

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Oh! I didn’t know that. Thanks for the info! Could that mean that theoretically someone could make an app to work with low frequency implants on Samsung phones?

I would highly doubt it, since it’s tied to the payment system I would imagine that samsung has it locked down pretty tight. And, I don’t think android itself has LF capabilities built in so it would have to go through a samsung framework most likely.

That’s not to say it’s physically impossible, and a Samsung phone likely has the hardware necessary for at least some light duty of programming of implants, I just don’t see it happening

I’m no expert on app development though, so maybe someone with actual experience in that area will pitch in soon

There’s also the possibility that it was a pulse from the wireless charging “Powershare”. Wireless charging operates near the same frequency as LF RFID and will light up the diagnostic card.


I hadn’t thought about that, but in my testing I’ve only seen it when you select a card through samsung pay, I don’t know if power share outputs power when it’s not actively being used but it’s certainly a possibility

The phone normally lights up the red though, not the green like it was doing when I selected the Samsung Pay app.

Samsung did developed a phone chip to read/write into 125kHz over a decade ago, and is is present in it’s phones, one way or another (maybe not all of it’s phones, so worth double checking)

So… technically, if you root it well and handle the firmware, it is technically feasible.

Although I would rather tackle that through a PinePhone or similar, using an NFC enabled case or dongle.

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Or break it, like mine

i must say i’ve been impressed overall with samsung’s willingness to shove strange shit into their phones… the S7 i have on my desk as a pulse oxymeter built in… nobody asked for it, it’s just there. now powershare and a magstripe interface… amazing.


To be fair tho, IMHO samsung really kicked off smartpay/phonepay. And I think a lot of this is because of the magstripe and the rfid HF in the samsung pay system. I’ve honestly found my samsung pay works more often on the first try then any other software or cards. What with most retail and restaurants having an older system that takes 2 or 3 goes before it recognizes your card… Working retail showed similar results as well, where samsung pay, due to all that weird shit in their phones, nearly always works, and often on the first try. Personally I use samsung pay all the time, except at gas stations(until I get frustrated and pay with my phone bc the card reader is not reading my card)
Sorry for the slightly verbose way of me saying I like samsung pay. Its one of the reasons I’m not super annoyed by a lack of an implantable payment chip.(that doesn’t need to be swapped every few yrs)