... . If there are four ports on the USB HUB, can connect 4 display meters, and so ... ,DC5V,DC12V,DC24V measure DC voltagevoltage meter with RS232, RS485 can be display the data ... in the screen of computer via USB ModelFull measurementResolutionAccuracyInput impedanceMax current input(A)MB4201 ... experience and 12 years experience cooperation with Panasonic voltage meter with RS232, RS485 can be display ...