T5557

T5557¶

Atmel T5557
- Contains 330 bits of data
- 10 blocks of 33 bits. 7 of witch are RW
- Operates at 125Khz
- Has Variable data rates
- Varable Modulation including Manchester, FSK, PSK, Biphase, NRZ.
- Password Protected R/W
- Direct access block read and write

Block 0 (Configuration Data)¶

Bits 0: Used to lock the Configuration so it cant be Written
Bits 1-11: 10 Digit Master Code
Bits 12-14: Bit Rate of Card
- 000: RF/8
- 001: RF/16
- 010: RF/32
- 011: RF/40
- 100: RF/50
- 101: RF/64
- 110: RF/100
- 111: RF/128
Bits 15: Unknown/Not Set
Bits 16-20: Modulation Type
- 00000: Direct
- 00001: PSK1
- 00010: PSK2
- 00011: PSK3
- 00100: FSK1
- 00101: FSK2
- 00110: FSK1a
- 00111: FSK2a
- 01000: Manchester
- 10000: BiPhase('50)
- 11000: Reserved
Bits 21-22:
- 00: RF/2
- 01: RF/4
- 10: RF/8
- 11: Reserved
Bits 23: Answer on Request Enabled
Bits 24: Unknown
Bits 25-27: The last Block that can be read. ex. If is 7 then can read blocks 0-7
Bits 28: Sets Password Mode
Bits 29: Sequence Terminator
Bits 30: Unknown/Not Set
Bits 31: Unknown/Not Set
Bits 32: Power on Reset. Delay IC Functionality until correct voltage

Initial Connection¶

When first loading up the Tag IC reads the internal Block 0 and sets the configuration information.
Start Block is sent with the Datablocks until it reaches the endblock then starts again with the Start Block.

Sending Read/Write Commands¶

https://www.priority1design.com.au/t5557_rfid_transponder.html

Emulate HID Card¶

A 75557 Card can emulate a HID card with some memory modifications.
http://proxmark.org/files/Documents/125%20kHz%20-%20HID/HID_format_example.pdf

Proxmark¶

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