... baud rate,300~115200bps 2.*3000VDC isolation protection 3.*Power Inputs +10~+30VDCAR-1520U/AR-1521U Features :Auto ... 1.1 / 2.0(Full Speed)No external power supply ( Power from the USB bus)Driver support Windows 98 / ... no need to open chassis or turn off PC power to install wiring hub, and you can get ... from USB port, and there is no need to use power adapter, therefore, it is widely applied to PLC, Modem, ...