Hi, About change "region": I implement the reader U107 (JRD-4035) with an USB to serial TTL UART interface (a TTL-232R-5V-PCB fron FTDI Chip) and can drive this reader with a serial terminal software as RealTerm (that supports frame of hex bytes) for simple tests (with Pyserial for a more evolved application). Then it is possible to check active "region" parameter, by send the command frame: 0xBB 0x00 0x08 0x00 0x00 0x08 0x7E. After a power On, the response is: BB 01 08 00 01 01 0B 7E corresponding to "China 900MHz" (01). We have to send the command: 0xBB 0x00 0x07 0x00 0x01 0x03 0x0B 0x7E to pass in "EU region", the reponse after the command: 0xBB 0x00 0x08 0x00 0x00 0x08 0x7E, is BB 01 08 00 01 03 0D 7E region parameter has well switched to "EU region" (03). (note: if the USB dongle is unplugged then plugged, the region parameter returns to '01') About documentation on this reader: I used this manual "https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/docs/datasheet/unit/uhf_rfid/MagicRF M100%26QM100_Firmware_manual_cn.pdf" and "translate Google tool" (the en version of the manual is not sufficient). Best, Thierry PS: the link between U107 and the FTDI interface module is: TXD/U107 to RXD/FTDI, RXD/U107 to TXD/FTDI, 5V to VCC and GND to GND.