3 ms·
NFC supports passive mode (where one side is powered and the card is not) and active mode (where both sides are powered). So, yes, your phone is probably more r
by kens 2y ago
NFC supports passive mode (where one side is powered and the card is not) and active mode (where both sides are powered). So, yes, your phone is probably more reliable because it provides a powered data transmission.
An NFC card doesn't actively transmit data. Instead, it sends data using "load modulation", where it switches a load across the antenna to change how much power it absorbs. The transmitter can detect this change in power, but the signal is extremely weak (80 decibels below the transmitted signal), so it's amazing that it works at all.
- Waterluvian 2y agoThat’s insane. And yet when I see what we can do with coax or twisted pair, I anticipate we’ll get to gbps speeds one day. :)
- lxgr 2y agoThe iPhone doesn't actually use NFC's peer-to-peer/"active" mode (since contactless payments aren't an NFC application; see my other comments on that), but it does specifically include an NFC "field amplifier" IC (shown in some iFixit teardowns), which most other smartphones and of course all physical cards/tags lack. This does mean that iPhones can't do cool tricks like booting up the secure element purely from the field with a completely dead battery though that some earlier Android and Windows Phones could do (or at least Apple has intentionally deactivated that capability for a more consistent/secure experience) :)