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Hotel key cards can look almost identical on the outside while using very different RFID technology on the inside. Two of the most common technologies hotel operators encounter are MIFARE Classic 1K and MIFARE Plus using AES security, often referred to in hospitality as AES or ULC cards.
Choosing the correct card matters because your lock system and encoder are programmed for a specific technology. A card with the wrong chip may look right, print correctly, and still fail when you try to encode or use it.
What is MIFARE Classic 1K?
MIFARE Classic 1K is one of the most widely used RFID card technologies in hospitality. It has been used for years across many hotel lock systems and remains a practical, cost-effective choice for properties whose systems are configured for 1K cards.
The “1K” refers to the card’s memory capacity. For hotel operators, the important point is simple: if your lock system and encoder are set up for MIFARE Classic 1K, you need a compatible 1K card.
What is MIFARE Plus / AES?
MIFARE Plus is a newer RFID technology designed to support stronger security. In many hotel environments, these cards are used with AES encryption and may be described as AES or ULC cards.
Some newer or upgraded hotel lock systems require this technology. A MIFARE Plus/AES card can look exactly like a Classic 1K card, which is why visual inspection alone is not enough to determine compatibility.
MIFARE Classic 1K vs MIFARE Plus (AES/ULC)
| Feature | MIFARE Classic 1K | MIFARE Plus / AES (ULC) |
|---|---|---|
| Security | Established RFID security | Enhanced security with AES support |
| Common use | Widely used in many hotel systems | Used in many newer or upgraded systems |
| Compatibility | Works with systems configured for Classic 1K | Works with systems configured for MIFARE Plus/AES |
| Appearance | Can look identical to AES cards | Can look identical to 1K cards |
| Best choice | Properties using 1K technology | Properties requiring AES/ULC technology |
Can I tell which card I have by looking at it?
Usually not. The artwork, logo, color, and printed design do not tell you what RFID chip is inside the card. Two cards can look exactly the same and use completely different technology.
The safest ways to identify your card are to check your lock-system requirements, confirm what your encoder is programmed for, review the card specification from your current supplier, or test a known sample.
Why the wrong card may not encode
If your hotel recently upgraded its locks or security configuration, you may find that cards that worked previously no longer encode correctly. This is especially common when a property moves from a Classic 1K configuration to a system requiring AES-capable cards.
If a card does not encode, that does not necessarily mean the card is defective. It may simply be the wrong RFID technology for your system.
Which hotel lock systems use 1K or AES cards?
Compatibility depends on the exact lock model, software version, and property configuration. Systems from major hospitality lock manufacturers such as Saflok/Dormakaba, Onity, and VingCard/ASSA ABLOY may support different card technologies depending on the installation.
That is why we recommend identifying the exact card technology your property uses instead of ordering based only on the lock brand.
Not sure which card you need?
We make it easy to verify compatibility before placing a full order. If you are unsure whether your property requires MIFARE Classic 1K, MIFARE Plus/AES, or another RFID card, contact Hotel & Resort Key Cards and we can help you identify the correct option.
We can also provide a free sample for testing so you can confirm that the card works with your encoder and locks before you order in quantity.