Animal identification runs at 134.2 kHz under ISO 11784/11785, using FDX-B encoding with a 15-digit country-animal-national code structure. The production floor here handles over 300,000 ICAR-certified glass tube microchips annually for a Turkish animal health company alone. Biocompatible glass coating prevents tissue rejection, and the chips remain readable for the animal's entire lifespan. Ear tag production reaches 500,000-600,000 sets monthly across cattle farm projects in Mexico, Mongolia, Senegal, Mauritania, and Botswana.

 High Frequency

The 13.56 MHz band operates under two major protocol families, and confusing them causes problems.

The original MIFARE Classic S50 provides 1KB of storage divided into 16 sectors, each containing four 16-byte blocks. Each sector maintains independent access control with two 6-byte keys (Key A and Key B) and a 4-byte access conditions field. The bit structure defining read, write, increment, and decrement permissions for each block allows granular security configuration-or did, before the cryptographic collapse made it largely theoretical.

HF tag selection should separate three common 13.56 MHz use cases. ISO 14443A cards are suitable for close-range access, hotel locks, payment terminals and secure credentials. ISO 15693 labels offer longer vicinity reading for books, files and some item-level tracking. NFC tags such as NTAG213, NTAG215 and NTAG216 are designed for phone interaction, URL encoding, product authentication and smart posters. If a buyer only says "13.56 MHz tag", the specification is incomplete.

For hotel, ticketing, membership and identity projects, ISO 14443A 13.56 MHz smart cards are a safer starting point than a generic HF card request. For mobile-phone tap interactions, the NFC Forum 13.56 MHz NFC technology page is a useful neutral reference because NFC depends on short-range HF communication rather than long-range RFID reading.

 Ultra-High Frequency

UHF RFID between 860-960 MHz operates on completely different physics. Instead of inductive coupling, UHF uses electromagnetic backscatter, enabling read distances of 10-15 meters with fixed readers and batch identification of 200+ tags per second.

The EPC Gen2 standard (ISO 18000-6C) defines memory organization across four banks. Reserved memory holds a 32-bit kill password and 32-bit access password. EPC memory contains a 16-bit CRC, protocol control bits indicating EPC length, and the Electronic Product Code itself-variable length starting at address 20h. TID memory stores the 8-bit ISO allocation class, 12-bit mask designer ID, and 12-bit tag model number. User memory varies by chip but provides space for application data. The GS1 EPC UHF Gen2 air interface protocol is the main neutral reference for this UHF standard family.

Security follows a state machine model. Tags in OPEN state accept basic commands. Providing the correct access password moves a tag to SECURED state, enabling lock and unlock operations. Three lock types exist: conditional write protection requiring the password, permanent write permission that cannot be locked, and permanent lock preventing any future writes.

Regional frequency allocation splits UHF deployments. North America uses 902-928 MHz. Europe operates at 865-868 MHz. This matters for international supply chain applications where tags cross borders.

UHF tag form factor matters more than many buyers expect. A paper wet inlay may perform well on cartons, but fail on a metal tool cabinet. A hard ABS tag may survive outdoors, but cost too much for disposable retail packaging. A laundry tag needs heat, pressure, chemical and washing-cycle resistance. A windshield label must be tuned for glass and controlled vehicle read zones. For projects that need fixed portals or gate reading, the tag should be tested together with long-range UHF RFID readers before mass encoding.