Optical multimeters are essential for deploying fiber optic communications and networking, and they stand as the core of the optical test and measurement. The increasing appetite for high-speed internet and growing data networks also translates to the need for rigorous testing. A multimeter is an advanced electronic measuring instrument that integrates multiple functions, serving as a voltmeter, ammeter, and ohmmeter in one device. It provides precise measurement values that can help determine which component. The multimeter is basically a digital version of an AVOmeter, which was designed in the early 1920s by British Post Office engineer Donald Macadie to measure amps, volts and ohms (hence "avo").