# Programmable RFID Cards ## What Are Programmable RFID Cards? **Programmable RFID cards** are versatile contactless smart cards that allow users to write, rewrite, and manage data stored on their embedded RFID (Radio-Frequency Identification) chip. Unlike simple, factory-preprogrammed RFID tags, these cards offer flexibility for access control, payment systems, data collection, and countless custom applications. From my personal experience working in office security management, transitioning from static keycards to **programmable RFID cards** was transformative. It allowed our team to issue, revoke, or update employee access privileges in real-time without needing to replace physical cards—a significant upgrade in both security and operational efficiency. ### Core Technology and How They Work The functionality hinges on the card's microchip and antenna. When brought near an RFID reader, the reader's electromagnetic field powers the chip via inductive coupling (for passive cards), enabling it to transmit its stored data. The "programmable" aspect means this data can be altered by an authorized writer/programmer device. #### Personal Skill Application: Programming a Custom Access System A practical case of using a personal skill involved programming these cards for a small library's membership system. I used a desktop RFID writer and simple software to encode each card with a unique member ID and tier level (e.g., child, adult, patron). This hands-on project demonstrated how a basic understanding of RFID protocols and database management could create a tailored, efficient solution. ### Technical Specifications and Parameters of Programmable RFID Cards For those integrating **programmable RFID cards** into a solution, understanding technical specifications is crucial. Here are detailed parameters for a common high-frequency (HF) card model. **Model:** TIANJUN Pro-Card HF-13.56MHz * **RFID Frequency:** 13.56 MHz (High Frequency) * **Protocol/Standard:** ISO/IEC 14443 A * **Chip Code:** NXP MIFARE Classic 1K (MF1S503x) * **Memory Capacity:** 1KB EEPROM, organized into 16 sectors with 4 blocks each (64 blocks total). Each block holds 16 bytes. * **Data Retention:** Minimum 10 years. * **Read/Write Cycles:** 100,000 cycles per block. * **Operating Range:** Up to 10 cm (depending on reader power). * **Dimensions:** Standard ID-1 format: 85.6mm x 54.0mm x 0.76mm. * **Communication Interface:** Contactless UART. * **Security:** 3-pass authe