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1 | ------------------------------------------------------------------------------- | |
2 | T55xx 125kHz RFID write protocol | |
3 | ------------------------------------------------------------------------------- | |
4 | ||
5 | This is a set of example captures from portable RFID copiers. | |
6 | ||
7 | Details: | |
8 | http://www.ebay.com/itm/RFID-125KHz-EM4100-Card-Copier-Duplicator-5-Writable-Cards-5-Keyfobs-Tags-/151237092163?hash=item23366ee343:g:lNkAAOxyYSdTBrVN | |
9 | http://www.ebay.com/itm/Handheld-Portable-125Khz-RFID-Duplicator-Copier-Writer-for-EM4100-T5577-Card-/191630611446?hash=item2c9e1313f6:g:D7UAAOSwyQtVo4pM | |
10 | http://priority1design.com.au/t5557_rfid_transponder.html | |
11 | http://www.atmel.com/Images/Atmel-9187-RFID-ATA5577C_Datasheet.pdf | |
12 | ||
13 | ||
14 | Logic analyzer setup | |
15 | -------------------- | |
16 | ||
17 | The logic analyzer used was a Saleae Logic 16 clone (at 2MHz): | |
18 | ||
19 | Probe T5557 write | |
20 | ----------------------- | |
21 | 1 RFID signal | |
22 | ||
23 | ||
24 | Data | |
25 | ---- | |
26 | ||
27 | To transmit data to the tag you turn on and of the coil for x amount of | |
28 | field clocks. This type of modulation is called OOK. | |
29 | ||
30 | The purpose of these RFID copiers are to read a generic EM4100 tag and | |
31 | copy the tag data to another tag. To do that you need to configure the | |
32 | destination tag and write specially formatted data in the tag banks. | |
33 | Thus the signal contains 4-5 write packets. | |
34 |