The invention generally relates to systems, devices, and methods for testing communication lines. In certain aspects, the invention provides systems and devices that include a digital/analog converter configured to operate with a computer processor and memory to send or receive an analog signal over a communication line that includes a plurality of signals having known frequencies. Inbound receiving sub-systems or devices sample the analog signal and measure a quality of the sampled, digital signal to evaluate the communication line. The key differentiator is the recognition that the human mouth and ear are intrinsically analog without encryption. By locating the test device as close to the user as possible, this system incorporates testing of complex communication streams including numerous variables and transforms (e.g. encryption, Analog to digital, Voice over IP, packet switching, ATM, SONET). Ultimately, it provides a simple interface to convert qualitative analysis to quantitative (numerical) analysis.