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125 KHz RFID Module

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125 KHz RFID Support

Please notice that, S125 Proximity Readers built on different hardware and firmware system if compared with SM125-IC chip and SM125-M1 module.

S125 Proximity Reader includes more advanced features such as supporting standalone mode with an EEPROM memory interface. 

SM125-IC, SM125-M1 modules do not support these new features, and their working principle including the communication protocol is different.




125 KHz RFID IC & Modules | Print |

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You can navigate our 125 KHZ RFID - IC & MODULES products in the List below, and click on the below tabs for more information and features.


Product List

Product ID Product Name
 SM125-M1-232125 KHz RFID Module with ST232
  • 125 KHz RFID OEM Module Integrated with ST232 IC (RS232 Diver IC)
  • 28 pin - 600 mil DIP Module
  • 3.7 x 2.0 cm
SM125-M1125 KHz RFID Module without ST232
  • 125 KHz RFID OEM Module without ST232 IC
  • 28 pin - 600 mil DIP Module
  • 3.7 x 2.0 cm
 SM125-IC125 KHz RFID Chip
  • Main core of the SM125 modules. Programmed MCU, analog & digital blocks integrated in a single system on chip.
  • 28 pin SOIC







General Information

SM125 RFID module/chip is designed for 125 KHz RFID applications. It's main advantages are; ease-of-use, rapid product development and cost effective. It is the first and unique design in the industry combining analog circuit and microcontroller in a single, mixed signal array chip.

Designers' most demanded features are embedded in the SM125 and is usable without deep understanding the technical concepts of RFID , resulting in profoundly shorter design time.

SM125 has tremendous features. Unlike any competitors' chip, SM125 performs all complicated RFID processes such as amplifiying, filtering, demodulating, decoding and digitizing, automatically and make the tag data ready to be sent over UART-RS232 / I2C / Wiegand 26-bit / Custom defined protocol and can trigger Buzzer/LED/Relay circuit.

SM125 can be controlled over UART-RS232 /I2C or with its most valuable and unique feature can behave as automated without requiring any external controller.

SM125, previousy called CY8C0104/05, is the new name for our 125 KHz devices and comes with a new firmware version (V3.0). The previous BUILD5-SP1 version has been in the field for 4 years, proving the reliability and availability now comes with better and more features with V3.0 firmware. For migration and upgrading information please investigate AN520 application note.











  • Single chip including microcontroller, analog circuit and antenna driver results in World's lowest count and smallest RFID reader 
  • Available as IC and Module
  • Firmware upgrade-able for custom specific applications
  • Module requires only antenna and power supply to function, IC requires just few more passive components to function.
  • Automatically demodulates and decodes RF signal and make the actual tag data ready. No need to know about complicated RFID subject
  • Supports Atmel/Temic T55xx transponders and EM4100/02. (Unique)
  • Supports Manchester RF/32 and Manchester RF/64 modulations
  • 5V or 3.3V operation ( 3.3V option requires different firmware upgrade)
  • Supports hardware and software Sleep Operation
  • UART Interface up to 115200bps - I2C Interface up to 400KHz. Module comes with RS232 driver(optional)
  • Control-able General Purpose Outputs and Inputs 
  • Supports flexible and programmable Wiegand 26 bit output format 



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