... 20mA current output.Isolated OCT output: for frequency output (0~9999Hz), alarm driver, or totaliser pulse output, ON/OFF control, etc.Relay output 1A@125VAC ... or 2A@30VDC. For ON/OFF control, alarm driver, totaliser output, etc ... Alarm Driver: alarm signal can be transmitted to Relay or OCT output terminals to drive an external alarm.RS-232 ...