Signal Recovery has introduced operating software for its Model 3820 universal counter, which counts pulses at up to 125 MHz and outputs signal frequency, pulse high and low, duty cycle and logic level measurements. The ActiveX control feature eliminates the need for writing the low-level codes required for communication and allows the user to develop higher-level programs to run experiments. A Windows dialog application, SR3820Counter, selects input, specifies update rate and displays all eight output measurements. The SR3820Comms control provides all communications to and from the instrument. The software supports data logging of the output measurements to text files, with data being written in comma separated value format for import into other programs. The product can be used for photon counting and frequency measurement.