Overview

The 125kHz RFID Key Tag (EM4100) is a high-quality proximity ID token designed for use with RFID access control systems.
It’s durable, passive, and maintenance-free — simply present it to a reader to grant access.
With waterproof ABS construction and universal compatibility, it’s ideal for offices, schools, and secure areas.

Specifications

Package

• 1 × 125kHz RFID Key Tag (EM4100 Type)

What is RFID Key Tag?

An RFID Key Tag is a small, contactless ID token that uses radio-frequency identification (RFID)
technology to transmit a unique ID when brought near a compatible reader.
It’s commonly used in access control systems for security and identification purposes.

How the RFID Key Tag Works

The RFID Key Tag contains an embedded EM4100 chip and antenna coil. When it’s close to an RFID reader,
the reader’s electromagnetic field powers the chip, which then transmits its unique ID number wirelessly.
The system verifies this ID to grant or deny access — all without physical contact.

Applications

• Door access control systems
• Employee attendance systems
• Hotel and apartment smart locks
• Parking management systems
• Identification and tracking solutions
• RFID-based automation projects

FAQ

• Q1: Does this tag need a battery?
  A1: No, it’s a passive tag that draws power from the RFID reader’s signal.
• Q2: Is it waterproof?
  A2: Yes, the ABS plastic enclosure makes it water-resistant and durable.
• Q3: Can it work with Arduino RFID readers?
  A3: Yes, it’s fully compatible with 125kHz RFID modules like RC522 and RDM6300.
• Q4: What is the reading range?
  A4: Typically between 2 to 5 inches, depending on the reader’s strength.
• Q5: Can I reprogram the ID?
  A5: No, EM4100 tags are read-only and come with a unique factory-programmed ID.

Reference Links

• EM4100 RFID Tag Datasheet
• How RFID Works – RFID Journal