The 520B Universal Test System is a plug-in module for either the 504A mainframe (which provides operating voltages), or the 500B mainframe (which provides operating voltages and contains a dual-memory storage scope for detection of signal impairment). The 520B performs all primary measurements necessary to qualify voice bandwidth circuits for data transmission. Analog parameters tested include envelope delay, attenuation distortion, P/AR, and all hit parameters.
