... computer can be realized by TCP/IP, RS485, USB, optional GPRS wireless network. 4. Build in backup battery can avoid data ... , 1:N (N≤3000) 15. Communication: TCP/IP, RS485, USB, GPRS(optional) 16. Separated Time Attendance & Separated Access Control: Support 17 ... *128*50.5 (mm) 24. Optional: Card Reader, Backup Battery, GPRS, Printer 25. Power Supply: DC9V, 1A/DC12V,2A(AC110V-220V ...