Table of Contents
1. Instruction.
2. What is an EM4100 card?
3. What is the frequency of an EM4100 card?
4. How are EM4100 cards powered?
5. How do EM4100 cards communicate with a reader?
6. What are EM4100 cards used for?
7. What is the difference between TK4100 and EM4100?
8. What are the different types of EM cards?
9. Can EM4100 cards be rewritten or cloned?
10. What are the advantages and limitations of EM4100 cards?
11. How to identify if your card is an EM4100 type?
12. What are the modern alternatives to EM4100 cards?
13. Conclusion
1. Instruction.
EM4100 cards are a mature low-frequency (125 kHz) RFID solution, widely used in access control, attendance, and asset management applications that require low security, thanks to their low cost, reliability, and durability.
Though simple in appearance, these cards communicate with readers via radio frequency, enabling fast and convenient identification.
Understanding the working principle, features, and applications of EM4100 cards can help businesses and individuals make smarter decisions when choosing or customizing RFID cards.
2. What is an EM4100 card?
The EM4100 card is a contactless radio frequency identification (RFID) card, classified as a read-only type RFID chip. It is mainly used in identity recognition, access control systems, and logistics management. The product is made with PVC or ABS encapsulation materials and conforms to ISO standard card or thick card form factors, operating at a typical frequency of 125 kHz.
The card integrates an EM4100/EM4102 RFID chip, which obtains power and clock signals through an external antenna coil. It uses a current-type switch modulation method to transmit 64-bit data. The data structure consists of 9 start bits, 40 data bits, 14 parity bits, and 1 stop bit, with a unique code programmed and stored via laser writing.
The product also incorporates a 74 pF resonant capacitor and a full-wave rectifier, ensuring compatibility with the TK4100 model and featuring low power consumption characteristics.
3. What is the frequency of an EM4100 card?
The EM4100 card operates at a low frequency of 125 kHz, which is the standard working frequency for low-frequency (LF) RFID systems. This frequency allows the card to communicate effectively with compatible RFID readers over a short range, typically between 2 and 10 centimeters, depending on the size and quality of the antenna used. Operating at 125 kHz gives the EM4100 card strong resistance to interference from non-metallic materials, making it reliable for use in environments where consistency and stability are important, such as access control, attendance tracking, and identification systems.
4. How are EM4100 cards powered?
EM4100 cards are passively powered, meaning they do not contain any internal battery or power source. Instead, they obtain the energy they need to operate from the electromagnetic field generated by an RFID reader operating at 125 kHz. When the card enters this field, the coil antenna embedded inside it induces an electric current through electromagnetic induction. This induced energy is then rectified and regulated by the card’s internal circuitry to power the EM4100 chip. Once powered, the chip transmits its unique 64-bit identification code back to the reader using amplitude shift keying (ASK) modulation. This passive power mechanism makes EM4100 cards maintenance-free, durable, and highly reliable for long-term use.
5. How do EM4100 cards communicate with a reader?
EM4100 cards are passive RFID (Radio Frequency Identification) cards operating at 125 kHz, and they communicate with a reader using low-frequency electromagnetic induction. Let me break it down step by step:
a. Passive Card – No Power Source
EM4100 cards do not have a battery. They rely entirely on the reader’s electromagnetic field to power their internal circuitry. The card has a coil (antenna) and a small IC (integrated circuit) containing the stored ID number. When placed near a reader, the reader emits a 125 kHz magnetic field. This magnetic field induces a current in the card’s coil, temporarily powering the chip.
b. Modulation – How Data is Sent
Once powered, the card communicates by modulating the magnetic field. EM4100 cards use ASK (Amplitude Shift Keying) or OOK (On-Off Keying) to encode data. Essentially, the card varies the load on its antenna coil, which slightly changes the amplitude of the magnetic field. The reader senses these tiny variations to detect the card’s data.
c. Data Format
EM4100 cards transmit a unique 64-bit ID code. The code is sent as serial data (one bit at a time) using Manchester encoding for error detection.
d. Reader Detection
The reader monitors the magnetic field. When it detects the modulated signal from the card, it decodes it into the unique ID number. The reader can then send this ID to a controller or access system.
6. What are EM4100 cards used for?
EM4100 cards are low-frequency (125 kHz) passive RFID cards, and their primary use is for identification and access control. Here’s a detailed breakdown of common applications:
a. Access Control Systems
· Building entry: Office doors, warehouses, residential complexes.
· Secure areas: Laboratories, server rooms, and restricted zones.
Often integrated with card readers and electronic locks.
b. Time and Attendance Tracking
· Used in workplaces to log employee check-ins and check-outs.
· The card’s unique ID allows the system to track who is present and when.
c. Asset Tracking
· Tagged on equipment or devices to monitor inventory or prevent theft.
· Easy scanning with a 125 kHz reader makes it suitable for low-cost asset tracking.
d. Identification Badges
· Membership cards for clubs, gyms, or libraries.
· Often combined with photo IDs for visual verification.
e. Parking Systems
· For vehicle access control in parking lots or gated communities.
· The card can be linked to a specific vehicle or user account.
f. Low-Security Applications
· Vending machines, cafeteria systems, or small-scale loyalty programs.
· EM4100 cards are read-only, so they are suitable where data does not need to be updated.
g. Key points about usage:
· Read-only ID: Cannot store extra user data or be rewritten.
· Short range: Typically 5–10 cm from the reader.
· Low cost: Makes them ideal for large-scale deployment where high security isn’t critical.
7. What is the difference between TK4100 and EM4100?
The TK4100 and EM4100 are both 125 kHz passive RFID cards, and they are very similar, but there are subtle differences that are important depending on the reader or system being used. Let’s break it down clearly:
(对比详细在chatgpt)
8. What are the different types of EM cards?
a. By Chip / Functionality:
· EM4100 – Read-only, 64-bit unique ID, basic access control.
· EM4102 – Similar to EM4100, factory options, 64-bit read-only.
· EM4200 / EM4205 – Read-only, 128-bit or more, longer codes.
· EM4305 – Read/write, 512-bit user memory, programmable IDs.
· EM4450 / EM4455 – Advanced read/write, larger memory, optional security/encryption.
b. By Form Factor:
· PVC cards – Standard card size for offices, gyms, access control.
· Key fobs / tokens – Small, durable, for keyrings or pockets.
· Wristbands – Flexible, for events, parks, hospitals.
· Stickers / labels – Thin, adhesive, for asset or inventory tracking.
c. By Capability:
· Read-only – EM4100, EM4102 (fixed unique ID).
· Read/write – EM4305, EM4450 (programmable memory).
· Enhanced security – EM4450 series (encryption/password options).
9. Can EM4100 cards be rewritten or cloned?
No — an original EM4100 chip is read‑only and cannot be rewritten. Yes — its ID can be cloned onto other programmable 125 kHz devices, so duplicates that behave like the original are possible.
Details (brief & clear)
· EM4100 itself: true ROM, passive, read‑only 64‑bit UID — you cannot change the UID on the original EM4100 tag.
· Cloning (what that means): someone can read the UID from an EM4100 and create a separate tag that transmits the same UID. The system that only checks the UID will treat the clone as the original.
· How clones are typically made (high level): vendors use programmable 125 kHz chips or pre‑programmed “compatible” tags to reproduce the same UID. (I’m not giving step‑by‑step instructions.)
· Practical reality: because EM4100 offers no built‑in authentication or crypto, cloning/duplication is relatively easy and common. Systems that rely solely on EM4100 UIDs are low‑security.
Important legal/ethical note
· Cloning or duplicating cards without the owner’s permission may be illegal and/or a breach of policy — don’t do it unless you have explicit authorization.
10. What are the advantages and limitations of EM4100 cards?
a. Advantages
· Low Cost – Very inexpensive, ideal for mass deployment.
· Simplicity – Easy to implement; just a 64-bit read-only ID.
· Passive Operation – No battery required; powered by the reader’s electromagnetic field.
· Durability – PVC cards or fobs are robust and long-lasting.
· Wide Compatibility – Works with most 125 kHz EM readers; TK4100 clones also compatible.
· Small & Flexible Form Factor – Cards, key fobs, wristbands, stickers.
b. Limitations
· Read-Only – Cannot store extra user data; the UID is fixed.
· Low Security – No encryption, no authentication; easy to clone.
· Short Range – Typically 5–10 cm; cannot read at a distance.
· Low Data Capacity – Only a 64-bit ID, unsuitable for complex applications.
· Susceptible to Interference – Can be affected by metal surfaces or strong electromagnetic fields.
· Obsolete Technology – Less secure and flexible compared to HF/NFC smartcards like MIFARE.
11. How to identify if your card is an EM4100 type?
a. Check the Frequency
EM4100 cards operate at 125 kHz (low frequency, LF). If you have a reader that can display the card’s frequency, a 125 kHz reading is a strong clue.
b. Check for Manufacturer Markings
Some EM4100 cards may have “EM4100” printed on the card, fob, or packaging. Other compatible clones (TK4100) may not show EM4100, but still behave the same.
c. Read the UID with a Compatible Reader
Use a 125 kHz EM reader. EM4100 transmits a 64-bit UID in Manchester encoding. If your reader successfully reads a 64-bit UID from the card, it is likely EM4100 or a compatible variant.
d. Physical Form Factor
Usually PVC cards, key fobs, wristbands, or stickers. EM4100 is passive, so there’s no battery or chip replacement inside.
e. Test Write Capability
EM4100 is read-only. If the card cannot be programmed or rewritten by a standard EM4305 programmer, it’s likely EM4100.
f. Use a Frequency/Chip Analyzer (Optional)
Devices like a 125 kHz RFID tester can identify the chip type. EM4100 will be recognized as a read-only 64-bit EM Microelectronic chip.
12. What are the modern alternatives to EM4100 cards?
Here are the modern, commonly used alternatives to EM4100, presented concisely so you can compare at a glance.
· MIFARE DESFire (EV1/EV2/EV3) (13.56 MHz, ISO14443A)
· MIFARE Plus (13.56 MHz, better security than Classic)
· MIFARE Classic (13.56 MHz — legacy, inexpensive, but insecure)
· NTAG / NTAG21x (NXP) (13.56 MHz, NFC tag family)
· ICODE / ISO15693 (13.56 MHz, longer HF read range / inventory)
· HID iCLASS / iCLASS SE / Seos (13.56 MHz, strong enterprise features)
· Smartcards with secure element / JavaCard (ISO 7816 / contactless)
· NFC (phones & tags) (13.56 MHz, phone-based access & credential provisioning)
· UHF EPC Gen2 (860–960 MHz) (long-range asset tracking)
· BLE / Bluetooth Low Energy tokens (active, mobile-friendly, longer range)
· Multi‑tech cards (combo cards combining LF + HF + barcode / BLE)
13. Conclusion
EM4100 cards are a mature, low-cost, and reliable 125 kHz low-frequency RFID solution, mainly used for access control, attendance, and asset management in low-security applications. Their simplicity, durability, and wide compatibility make them still very popular in small offices, schools, and other low-security systems.
If you want to maintain compatibility while customizing for personalized or large-scale orders, CBT Factory offers professional RFID card customization services, including PVC cards, key fobs, wristbands, and more, with support for bulk printing or encoding.
Visit CBT Factory now to leave a message and customize your exclusive RFID cards!
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