Knowledge base
RFID reader guides: selection, setup and standards
Technical answers to the questions buyers and integrators ask before choosing a reader: which card it reads, what it outputs, how it connects and what to expect on range.
Selection guides
125kHz vs 13.56MHz: Which RFID Card Reader Do You Need?
A 125kHz reader reads only 125kHz proximity cards such as EM4100 and TK4100. A 13.56MHz reader reads only HF cards such as MIFARE Classic, NTAG or ICODE. Neither reads the other's cards, so identify the card first. Match existing cards; for a new project, 13.56MHz offers more chip choice, on-card memory and phone compatibility.
Read guide →ISO 14443 vs ISO 15693: Proximity Cards, Vicinity Tags and Choosing an HF Reader
ISO/IEC 14443 and ISO/IEC 15693 both run at 13.56 MHz but use different air interfaces. ISO 14443 proximity cards such as MIFARE and NTAG work within about 10 cm and suit access, payment and ID. ISO 15693 vicinity tags such as ICODE wake in a weaker field, read farther with large antennas and suit library and item labels.
Read guide →USB, RS232, RS485 or Wiegand? How to Choose an RFID Reader Interface
Choose the interface from the device that receives the card number. USB keyboard emulation suits PC and Android software that accepts typed input. RS232 suits a COM port within about 15 m. RS485 suits long or shared runs up to about 1,200 m. Wiegand suits door access controllers, and TCP/IP suits readers that report to a networked server.
Read guide →Technology explained
EM4100 vs TK4100 Cards: How the 64-Bit ID Becomes a Card Number
EM4100 and TK4100 are interchangeable read-only 125kHz chips. Each sends one thing to a reader: a fixed 64-bit code carrying a 32-bit ID number. The card has no writable memory and no security. Readers show the ID as a 10-digit decimal, 8-digit hex or Wiegand facility and card number, so pick the format your system stores.
Read guide →Magnetic Stripe Tracks 1, 2 and 3 Explained (Plus HiCo vs LoCo)
An ISO magnetic stripe has three tracks. Track 1 stores up to 79 alphanumeric characters at 210 bpi, Track 2 up to 40 digits at 75 bpi, and Track 3 up to 107 digits at 210 bpi. HiCo (about 2,750 Oe) and LoCo (about 300 Oe) describe how hard a stripe is to write or erase, not which tracks it holds.
Read guide →MIFARE Classic vs Ultralight vs NTAG213: Which Chips Will Your Reader Read?
MIFARE Classic, MIFARE Ultralight and NTAG213 are all ISO/IEC 14443A chips at 13.56 MHz, so any 14443A reader can read their UID. They differ in UID length (usually 4 or 7 bytes), memory and security. Reading memory or NDEF records needs a read/write reader; a UID-only keyboard reader outputs the chip's serial number only.
Read guide →NFC Reader vs RFID Reader: Can an NFC Reader Read 125kHz Cards?
NFC is a 13.56MHz subset of RFID. An NFC reader, including a phone, reads 13.56MHz cards and tags such as MIFARE and NTAG, but it cannot read 125kHz EM4100 or TK4100 cards, 134.2kHz animal microchips or UHF tags. No app or update changes this. Those tags need a reader built for their frequency.
Read guide →RFID Card Number Formats: 10-Digit Decimal, 8H Hex, Wiegand 26 and Byte Order
An RFID card stores one binary ID, but readers, card printers and controllers display it in different formats. The same EM4100 card can appear as 0793541918 (10-digit decimal), 2F4C7D1E (8-digit hex) or 076,32030 (Wiegand 26). Mismatches almost always come from base, truncation or byte order, not from a faulty card.
Read guide →What Is a Keyboard Wedge Reader? USB HID Keyboard vs Virtual COM vs PC/SC
A keyboard wedge is a reader that presents itself to the computer as a USB keyboard. When a card is presented, it types the card number, often followed by Enter, wherever the cursor is. It needs no driver or SDK, but data flows one way only. Choose virtual COM or PC/SC when software must control the reader.
Read guide →Integration & setup
How to Use an External NFC or RFID Reader on Android (USB-C OTG Checklist)
An external USB-C reader lets an Android phone or tablet read cards its built-in NFC cannot, or read them without a custom app. The device must support USB OTG host mode. The reader takes power from the port and types each card number into the focused field like a keyboard, so check OTG, keyboard layout, focus and output format first.
Read guide →RFID Reader Not Reading Cards? A 10-Step Troubleshooting Checklist
When an RFID reader does not read a card, the cause is usually a mismatch, not a fault. Check power first, confirm the card's frequency and standard, present one card flat within range, then find where the output goes. Test with a known-good card in a text editor before you blame the reader or your software.
Read guide →RFID Reader to Excel: How to Read Card Numbers into a Spreadsheet (No Coding)
Use a keyboard-emulation RFID reader. It types each card number into the selected Excel cell like a keyboard, often followed by Enter. Format the column as Text before the first read so leading zeros survive, then add a timestamp, a name lookup and a duplicate check. No driver, add-in or code is required.
Read guide →Access control
Wiegand 26 vs Wiegand 34: Bit Layout, Facility Code and Card Number
Wiegand 26 and Wiegand 34 use the same two data wires and timing; they differ in how many ID bits reach the controller. A 26-bit frame carries 24 data bits (8-bit facility code 0–255 plus 16-bit card number 0–65,535) between two parity bits. A 34-bit frame carries 32 data bits, so a full 4-byte card ID arrives intact.
Read guide →Wiegand Wiring Diagram: Reader Wire Colors, Cable Distance and Common Faults
A Wiegand reader needs four core connections: +V (usually 12 V DC), GND, D0 and D1, plus optional LED and buzzer control. Tie the reader and controller grounds together, use shielded stranded cable and check the voltage at the reader under load. Most faults on site come from swapped D0/D1, a missing common ground or a format mismatch.
Read guide →UHF RFID
Fixed vs Handheld UHF RFID Readers, and Where Integrated Readers Fit
Choose by what moves. If tagged vehicles, pallets or people pass a fixed point, use a fixed or integrated reader. If staff walk to tags on shelves or assets, use a handheld. If a person presents one tag at a desk, use a desktop reader/writer. An integrated reader houses reader and antenna together, so it installs as one unit.
Read guide →How to Write UHF RFID Tags: EPC, TID, User Memory, Passwords and Lock
Writing a UHF RFID tag means changing its Gen2 memory with a reader/writer: usually the EPC, sometimes user memory, then the passwords and lock state. The TID is programmed and locked by the chip maker, so on standard chips it cannot be rewritten. Encode one tag at a time at low power, read back every write, and set a nonzero access password before locking.
Read guide →UHF RFID Anti-Collision and Multi-Tag Read Rates: Q, Sessions, Antennas
A UHF reader separates many tags by anti-collision: each Gen2 tag answers in a random time slot set by the Q value, and tags already read stay quiet according to their session flag. To raise multi-tag read rates, fix tag placement and antenna layout first, then tune RF power, session, target and Q, and count unique tags read.
Read guide →UHF RFID Frequency by Country: Bands, Power Limits and Ordering Tips
UHF RFID has no single worldwide band. The US, Canada and Mexico use 902–928 MHz at 4 W EIRP; the EU and UK use 865.6–867.6 MHz at 2 W ERP; India uses 865–867 MHz; China 920.5–924.5 MHz; Japan 916.7–920.9 MHz. EPC Gen2 tags work in all of them, but each reader must be supplied for the country where it operates.
Read guide →UHF RFID Read Range: Why One Reader Reads 0.5 m and Another 20 m
UHF RFID read range depends on how much reader power reaches the tag chip. That depends on radiated power (EIRP), capped at 4 W EIRP in the US and 2 W ERP in the EU, on the tag's chip and antenna, and on what the tag is mounted on. Desktop readers are built for 0.5 m, gate readers for meters.
Read guide →Animal ID
Can You Scan a Microchip with Your Phone? Pet Chips, NFC and 134.2kHz
No. A phone's NFC works only at 13.56MHz, while ISO pet microchips work at 134.2kHz, so no app can read an implanted chip with the phone alone. A phone can show the number if you add a 134.2kHz reader: a USB-C plug-in for Android, or a handheld scanner that sends the ID over Bluetooth.
Read guide →FDX-B vs HDX Animal Tags: How They Differ and What Your Reader Must Support
FDX-B and HDX are the two ways ISO 11785 lets a 134.2kHz animal tag send the same 64-bit ISO 11784 ID. An FDX-B tag replies while the reader's field is on. An HDX tag stores energy, then replies while the field is off. A reader reads HDX tags only if it supports HDX.
Read guide →ISO 11784 and 11785 Explained: How the 15-Digit Animal ID Number Is Built
ISO 11784 defines the 64-bit code stored in an animal RFID tag. ISO 11785 defines how a 134.2kHz reader powers the tag and receives that code, by FDX-B or HDX. Readers usually show the code as 15 digits: a 3-digit country or manufacturer code, then a 12-digit national ID.
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